Eiffel Tower

Eiffel Tower History

The Eiffel Tower was built for the International Exhibition of Paris of 1889 commemorating the centenary of the French Revolution. The Prince of Wales, later King Edward VII of England, opened the tower. Of the 700 proposals submitted in a design competition, Gustave Eiffel's was unanimously chosen. However it was not accepted by all at first, and a petition of 300 names - including those of Maupassant, Emile Zola, Charles Garnier (architect of the Opéra Garnier), and Dumas the Younger - protested its construction.

At 300 meters (320.75 m including antenna), and 7,000 tons, it was the world's tallest building until 1930. Other statistics include:

2.5 million rivets

300 steel workers, and 2 years (1887-1889) to construct it.

Sway of at most 12 cm in high winds.

Height varies up to 15 cm depending on temperature.

15,000 iron pieces (excluding rivets). 40 tons of paint. 1652 steps to the top.

In 1889, Gustave Eiffel began to fit the peak of the tower as an observation station to measure the speed of wind. He also encouraged several scientific experiments including Foucault's giant pendulum, a mercury barometer and the first experiment of radio transmission. In 1898, Eugene Ducretet at the Pantheon, received signals from the tower.

According to NASA climate scientist Jay Zwally, the 'Arctic is the canary in the coal mine.' What do you think would happen to the Eiffel Tower due to global warming? Please send your thoughts to our Webmaster! ... and do not be surprised if these are published on our Web site.

After Gustave Eiffel experiments in the field of meterology, he begun to look at the effects of wind and air resistance, the science that would later be termed aerodynamics, which has become a large part of both military and commercial aviation as well as rocket technology. Gustave Eiffel imagined an automatic device sliding along a cable that was stretched between the ground and the second floor of the Eiffel Tower. (reference)

The tower was almost torn down in 1909, but was saved because of its antenna used both for military and other purposes, and the city let it stand after the permit expired. When the tower played an important role in capturing the infamous spy Mata Hari during World War I, it gained such importance to the French people that there was no more thought of demolishing it.- used for telegraphy at that time.

From 1910 and on the Eiffel Tower became part of the International Time Service. French radio (since 1918), and French television (since 1957) have also made use of its stature.

During its lifetime, the Eiffel Tower has also witnessed a few strange scenes, including being scaled by a mountaineer in 1954, and parachuted off of in 1984 by two Englishmen. In 1923 a journalist rode a bicycle down from the first level. Some accounts say he rode down the stairs, other accounts suggest the exterior of one of the tower's four legs which slope outward. (reference)

Of the 7.5 million kilowatt hours of electricity used annually, 580 thousand are used exclusively to illuminate the tower. The tower's annual operation also requires the use of 2 tons of paper for tickets, 4 tons of rag or paper wipes, 10,000 applications of detergents, 400 liters of metal cleansers and 25,000 garbage bags. (reference)

On the four facades of the tower, the 72 surnames of leading turn-of-the-century French scientists and engineers are engraved in recognition of their contributions to science. This engraving was over painted at the beginning of the 20th century and restored in 1986-1987 by the Société Nouvelle d' Exploitation de la Tour Eiffel, a company contracted to operate business related to the Tower.

Other landmarks: Christ the Redeemer, Colossus, Delhi pillar, Eiffel tower, Golden Gate bridge, Great Buddha, Guggenheim Museum (Bilbao), Guggenheim Museum (NYC), Normandy bridge, Oresund crossing, Quebec Bridge, Statue of Liberty, Thames Barrier, Titanic, Tower of the Orologio

Mayon Volcano, Albay Philippines

 History of Mt.Mayon

                 

Mayon Volcano, also known as Mount Mayon, is an active stratovolcano in the province of Albay, in theBicol Region, on the island of Luzon, in the Philippines.

Renowned as the "perfect cone" because of its almost symmetrically conical shape, Mayon forms the northern boundary of Legazpi City. Local folklore refers to the volcano as Bulkang Magayon (Filipino: 'Magayon Volcano'), after the legendary heroine Daragang Magayon (Bikol: 'Lady Beautiful').^[2]

On October 13, 2008 it was included in New 7 Wonders of Nature Top 10 list. However, it did not make the cut to the Top 25 finalists, giving way to the Puerto Princesa Subterranean River, another site in the Philippines.

Geomorphology

Mayon Volcano is an active stratovolcano. The current cone was formed through pyroclastic and lava flows from past eruptions. Mayon is the most active of the active volcanoes in the Philippines, having erupted over 49 times in the past 400 years.

It is located on the eastern side of Luzon, beside the Philippine Trench which is the convergent boundarywhere the Philippine Sea Plate is driven under the Philippine Mobile Belt. Where a continental plate or belt of continental fragments meets an oceanic plate, the lighter continental material overrides the oceanic plate, forcing it down into the Earth's mantle. Magma, formed where the rock melts, may be forced through weaknesses in the continental crust caused by the collision of the tectonic plates. One such exit point is Mayon.

Like other volcanoes located around the rim of the Pacific Ocean, Mayon is part of the Pacific Ring of Fire.

Location and formation

Mayon Volcano is the main landmark of Albay Province, Philippines. It is 10 kilometres (6 mi) from the Gulf of Albay,^[3] in the municipalities of Legazpi City, Daraga, Camalig, Guinobatan, Ligao City, Tabaco City,Malilipot, and Santo Domingo (clockwise from Legazpi). It rises 2462 m (8,077 ft) above the gulf.^[4]

Mayon Volcano is the Philippines' most active volcano and is considered to be the world's most perfectly formed volcano^[3] for its symmetrical cone. It is a basaltic-andesitic volcano.^[4] The upper slopes of the volcano are steep averaging 35-40 degrees and are capped by a small summit crater. Its sides are layers of lava and other volcanic material.

Recorded eruptions

Mayon has undergone forty-nine eruptions in recorded history. The first recorded major eruption was in 1616. Its 48th and latest major eruption was a quiet effusion of lava on July 14, 2008 ,^[5], which was aggravated when a lahar caused by the rains of Typhoon Durian followed on November 30, 2006. A further summit eruption occurred on August 10, 2008.^[6] At present the volcano is weakly erupting and may be building up to a larger hazardous eruption.

The most destructive eruption of Mayon occurred on February 1, 1814. Lava flowed but not as much compared to the 1766 eruption. Instead, the volcano was belching dark ash and eventually bombarding the town with tephra that buried the town of Cagsawa—only the bell tower of the town's church remained above the new surface. Trees were burned; rivers were certainly damaged. Proximate areas were also devastated by the eruption with ash accumulating to 9 m (30 ft) in depth. 2,200 Albay locals perished in what is considered to be the most lethal eruption in Mayon's history.^[3]

Mayon Volcano's longest uninterrupted eruption occurred on June 23, 1897 which lasted for seven days of raining fire. Lava once again flowed down to civilization. Seven miles eastward, the village of Bacacay was buried 15 m (49 ft) beneath the lava. In Libon 100 people were declared dead—incinerated by steam and falling debris or hot rocks. Other villages like San Roque, Misericordia and Santo Niño became deathtraps. Ash was carried in black clouds as far as 160 km (100 mi) from the catastrophic event. More than 400 people were killed.^[3]

Samuel Kneeland, a professor and a geologist had observed the volcanic activity five months before the eruption. Kneeland was amazed with the beauty of Mayon:

At night the scene was truly magnificent and unique. At the date of my visit the volcano had poured out...a stream of lava on the Legaspi side from the very summit. The viscid mass bubbled quietly but grandly, and overran the border of the crater, descending several hundred feet in a glowing wave, like red-hot iron. Gradually, fading as the upper surface cooled, it changed to a thousand sparkling rills among the crevices, and, as it passed beyond the line of complete vision behind the woods near the base, the fires twinkled like stars, or the scintillions of a dying conflagration. More than half of the mountain height was thus illuminated.^[3]

No casualties were recorded from the 1984 eruption after more than 73,000 people were evacuated from the danger zones as recommended by PHIVOLCS scientists.^[7]

Pyroclastic flows killed 77 people, mainly farmers, in Mayon’s fatal eruption of 1993.

2006 eruption

Mayon erupted again from July to October 2006, with no apparent loss of life during the actual eruption period.

On July 18, 2006: The number and size of incandescent rockfalls from the active lava dome, as well assulfur oxide emissions, increased, according to the Philippines Institute of Volcanology and Seismology(Phivolcs), which warned that pyroclastic flows or an explosive eruption could occur any time.

On August 7, 2006: The Philippine government ordered the evacuation of about 20,000 people living near the volcano, stating that an eruption was feared soon.^[8] Volcanologists have detected 21 low-frequencyvolcanic earthquakes since early Sunday morning.^[9]

On August 8, 2006: The government expected to move some 34,276 people to 31 state-run shelters and warned that the mountain could explode at any time.^[10][11]

On August 9, 2006: Volcanologists warned that Mount Mayon could explode at any time but that the gravitational pull of a full moon could provide the final push. A full moon coincided with at least three of Mayon’s nearly 50 explosions over the last four centuries, including the two most recent in 2000 and 2001. Nearly 40,000 people have been moved from an 8 km (5 mi) danger zone on the southeast flank of the volcano, which has been quaking and spitting plumes of ash since July.^[12]

On August 10, 2006: Scientists in the Philippines renewed warnings of a major explosion at the Mount Mayon volcano, describing a sudden period of quiet as "ominous". A drop in gas emissions and earthquakes sparked fears that the crater had plugged itself, increasing the likelihood of an explosive eruption.^[13]

On August 11, 2006: Scientists said ground surveys showed Mayon was still "swollen" and registered a high number of volcanic earthquakes, emitted large amounts of sulfur dioxide gas and continued to eject lavadown its slope nearly four weeks after it came to life in a "quiet" eruption on July 14.^[14] Phivolcs maintained threat level at Alert Level 4 for the next month because of the continued extrusion of lava, ash explosions, steam and smoke plumes, seismic activity, and threat of further eruption.

On September 11, 2006 Phivolcs downgraded threat level to Alert Level 3. "After the ash explosion of September 1, a general decline in the overall activity of Mayon has been established. The decrease in key parameters such as seismicity, gas (Sulfur Dioxide) emission rates and ground inflation all indicate a waning condition. The slowdown in the eruptive activity is also evident from the decrease in intensity of crater glow and the diminishing volume of lava being extruded from the summit".^[15]

On October 3, 2006 Phivolcs downgraded threat level to Alert Level 2. "All monitored key parameters such as earthquake levels, ground deformation and gas outputs further declined. In addition, lava extrusion apparently ceased on October 1, 2006 as reported by Ligñon Hill Observatory. The above observations indicate the absence of an intruding new mass of magma." ^[16]

On October 25, 2006 Phivolcs downgraded threat level to Alert Level 1 (no hazardous eruption 

Sydney Opera House

Sydney Opera House (1957 - 1973) is a masterpiece of late modern architecture. It is admired internationally and proudly treasured by the people of Australia. It was created by a young architect who understood and recognised the potential provided by the site against the stunning backdrop of Sydney Harbour. Denmark’s Jørn Utzon gave Australia a challenging, graceful piece of urban sculpture in patterned tiles, glistening in the sunlight and invitingly aglow at night. Jorn Utzon died in Copenhagen in November 2008 aged 90.

In its short lifetime, Sydney Opera House has earned a reputation as a world-class performing arts centre and become a symbol of both Sydney and the Australian nation. 

World Heritage Listed 

Sydney Opera House was inscribed in the World Heritage List in June 2007: “Sydney Opera House is a great architectural work of the 20th century. It represents multiple strands of creativity, both in architectural form and structural design, a great urban sculpture carefully set in a remarkable waterscape and a world famous iconic building.” UNESCO

The expert evaluation report to the World Heritage Committee stated: “…it stands by itself as one of the indisputable masterpieces of human creativity, not only in the 20th century but in the history of humankind.”

Design/Structure 

The distinctive roof comprises sets of interlocking vaulted ‘shells’ set upon a vast terraced platform and surrounded by terrace areas that function as pedestrian concourses.

The two main halls are arranged side by side, with their long axes, slightly inclined from each other, generally running north-south. The auditoria face south, away from the harbour with the stages located between the audience and the city. The Forecourt is a vast open space from which people ascend the stairs to the podium. The Monumental Steps, which lead up from the Forecourt to the two main performance venues, are a great ceremonial stairway nearly 100 metres wide.

The vaulted roof shells were designed by Utzon in collaboration with internationally renowned engineers Ove Arup & Partners with the final shape of the shells derived from the surface of a single imagined sphere. Each shell is composed of pre-cast rib segments radiating from a concrete pedestal and rising to a ridge beam. The shells are faced in glazed off-white tiles while the podium is clad in earth-toned, reconstituted granite panels. The glass walls are a special feature of the building, constructed according to the modified design by Utzon’s successor architect, Peter Hall. 

History of the Design 

The history surrounding the design and construction of the building became as controversial as its design. In 1956 the NSW Government called an open-ended international design competition and appointed an independent jury. The competition brief provided broad specifications to attract the best design talent in the world; it did not specify design parameters or set a cost limit. The main requirement of the competition brief was a design for two performance halls, one for opera and one for symphony concerts. Reputedly rescued from a pile of discarded submissions, Jørn Utzon’s winning entry created great community interest and the NSW Government’s decision to commission Utzon as the sole architect was unexpected, bold and visionary. 

Construction 

Design and construction were closely intertwined. Utzon’s radical approach to the construction of the building fostered an exceptional collaborative and innovative environment. The design solution and construction of the shell structure took eight years to complete and the development of the special ceramic tiles for the shells took over three years. The project was not helped by the changes to the brief. Construction of the shells was one of the most difficult engineering tasks ever to be attempted. The revolutionnary concept demanded equally revolutionary engineering and building techniques. Baulderstone Hornibrook (then Hornibrook Group) constructed the roof shells and the interior structure and fitout. At the behest of the Australian Broadcasting Commission (ABC) the NSW Government changed the proposed larger opera hall into the concert hall because at the time, symphony concerts, managed by the ABC, were more popular and drew larger audiences than opera. 

Completion and Opening 

Cost overruns contributed to populist criticism and a change of government resulted in 1966 to Utzon’s resignation, street demonstrations and professional controversy. Peter Hall supported by Lionel Todd and David Littlemore in conjunction with the then NSW Government Architect, Ted Farmer completed the glass walls and interiors including adding three previously unplanned venues underneath the Concert Hall on the western side.  Opened by Queen Elizabeth II in 1973, new works were undertaken between 1986 and 1988 to the land approach and Forecourt under the supervision of the then NSW Government Architect, Andrew Andersons, with contributions by Peter Hall. 

For the future 

In 1999, Jørn Utzon was re-engaged as Sydney Opera House architect to develop a set of design principles to act as a guide for all future changes to the building. These principles reflect his original vision and help to ensure that the building’s architectural integrity is maintained.

Utzon Room 

Utzon's first major project was the refurbishment of the Reception Hall into a stunning, light filled space which highlights the original concrete 'beams' and a wall-length tapestry designed by him which hangs opposite the harbour outlook. Noted for its excellent acoustics, it is the only authentic Utzon-designed space at Sydney Opera House and was renamed the Utzon Room in his honour in 2004.

Modern Alterations

This project was followed by the first alteration to the exterior of the building with the addition of a new Colonnade along the western side, which shades nine new large glass openings into the previously solid exterior wall. This Utzon-led project, which was completed in 2006, gave the theatre foyers their first view of Sydney Harbour. The foyers' interiors are now being renovated to Utzon's specifications, to become a coherent attractive space for patrons. The design also incorporates the first public lift and interior escalators to assist less mobile patrons.

Utzon was working on designs to renovate the ageing and inadequate Opera Theatre. On all projects, he worked with his architect son Jan, and Sydney-based architect Richard Johnson of Johnson Pilton Walker.

Architecture Prize 

In 2003 Utzon received the Pritzker Prize, international architecture's highest honour.

Statue of Liberty

 The Statue of Liberty National Monument officially celebrated her 100th birthday on October 28, 1986. The people of France gave the Statue to the people of the United States over one hundred years ago in recognition of the friendship established during the American Revolution. Over the years, the Statue of Liberty's symbolism has grown to include freedom and democracy as well as this international friendship.

Sculptor Frederic Auguste Bartholdi was commissioned to design a sculpture with the year 1876 in mind for completion, to commemorate the centennial of the American Declaration of Independence. The Statue was a joint effort between America and France and it was agreed upon that the American people were to build the pedestal, and the French people were responsible for the Statue and its assembly here in the United States. However, lack of funds was a problem on both sides of the Atlantic Ocean. In France, public fees, various forms of entertainment, and a lottery were among the methods used to raise funds. In the United States, benefit theatrical events, art exhibitions, auctions and prize fights assisted in providing needed funds.

Meanwhile in France, Bartholdi required the assistance of an engineer to address structural issues associated with designing such a colossal copper sculpture. Alexandre Gustave Eiffel (designer of the Eiffel Tower) was commissioned to design the massive iron pylon and secondary skeletal framework which allows the Statue's copper skin to move independently yet stand upright. Back in America, fund raising for the pedestal was going particularly slowly, so Joseph Pulitzer (noted for the Pulitzer Prize) opened up the editorial pages of his newspaper, "The World" to support the fund raising effort. Pulitzer used his newspaper to criticize both the rich who had failed to finance the pedestal construction and the middle class who were content to rely upon the wealthy to provide the funds. Pulitzer's campaign of harsh criticism was successful in motivating the people of America to donate.

Financing for the pedestal was completed in August 1885, and pedestal construction was finished in April of 1886. The Statue was completed in France in July, 1884 and arrived in New York Harbor in June of 1885 on board the French frigate "Isere" which transported the Statue of Liberty from France to the United States. In transit, the Statue was reduced to 350 individual pieces and packed in 214 crates. The Statue was re-assembled on her new pedestal in four months time. On October 28th 1886, the dedication of the Statue of Liberty took place in front of thousands of spectators. She was a centennial gift ten years late.

The story of the Statue of Liberty and her island has been one of change. The Statue was placed upon a granite pedestal inside the courtyard of the star-shaped walls of Fort Wood (which had been completed for the War of 1812.) The United States Lighthouse Board had responsibility for the operation of the Statue of Liberty until 1901. After 1901, the care and operation of the Statue was placed under the War Department. A Presidential Proclamation declared Fort Wood (and the Statue of Liberty within it) a National Monument on October 15th, 1924 and the monument's boundary was set at the outer edge of Fort Wood. In 1933, the care and administration of the National Monument was transferred to the National Park Service. On September 7, 1937, jurisdiction was enlarged to encompass all of Bedloe's Island and in 1956, the island's name was changed to Liberty Island. On May 11, 1965, Ellis Island was also transferred to the National Park Service and became part of the Statue of Liberty National Monument. In May of 1982, President Ronald Reagan appointed Lee Iacocca to head up a private sector effort to restore the Statue of Liberty. Fundraising began for the $87 million restoration under a public/private partnership between the National Park Service and The Statue of Liberty-Ellis Island Foundation, Inc., to date the most successful public-private partnership in American history. In 1984, at the start of the Statue's restoration, the United Nations designated the Statue of Liberty as a World Heritage Site. On July 5, 1986 the newly restored Statue re-opened to the public during Liberty Weekend, which celebrated her centennial.

the Colosseum of Rome

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Colosseum is one of the greatest architecture ever built in the history of Rome. The Colosseum was originally known as the Flavian Amphitheatre and is the largest amphitheater to have ever been built in the Roman Empire. It is a circular structure that occupies a site east of the Roman Forum. This Amphitheater was built to organize gladiator contests, dramas and games like hunting animals, constructing mock sea battle and the public could also view it in the open, and cheer their favorites.

Built in the center of Rome itself, its construction began sometime between 70 and 72 AD and was completed in 80 AD when Titus was the ruling emperor. It has a seating capacity of 50,000 spectators. The Colosseum over the years has been broken by natural disasters like earthquake; even then, it is one of the hot spot of tourist visits in Rome. Very near to the Colosseum is the training school for the gladiators and it is worth the look. As compared to the oval shape of the Colosseum, it is triangular in shape. Other areas of attraction are places where the armor was built, then where the wounded gladiators were cured and not to forget the burial ground where the dead gladiators rested in peace.

Today, the Colosseum is used for religious purposes. The Pope leads a procession on good Fridays called the station of the cross. Currently, the Amphitheater is very rich in Flora. There are more then hundreds of different kinds of Flora present on the ancient walls of the Colosseum. The Colosseum of Rome has been given great importance by the media and that is the reason why a lot of Hollywood movies have been shot in this amphitheater. The famous movie “Gladiator” is highly influenced by the Roman culture and the gladiator contests.

Traveling to the Colosseum

The fascinating history that involves bloodbaths and battles associated with the structure is what draws visitors to this historical site. Getting to the Colosseum by taxi or bus from the airport is easy enough, but the line to get into the site itself can be excruciatingly long, especially during the very busy summer season. Aside from going there at any other time, there are other ways to get around these long lines. You can buy your ticket either at the Roman Forum or the Via de San Gregorio (these ticket counters are usually line-free), or you can even get them online. You can also buy a combo ticket that covers several of Rome’s main attractions, or call the office to reserve your ticket in advance. Another good way to avoid long lines at the Colosseum entrance is by joining a tour group.

The Great Wall of China

The history of the Great Wall is said to start from the Spring and Autumn Periods when seven powerful states appeared at the same time. In order to defend themselves, they all built walls and stationed troops on the borders. At that time, the total length of the wall had already reached 3,107 miles, belonging to different states.

In 221 BC, the Emperor Qin absorbed the other six states and set up the first unified kingdom in Chinese history. In order to strengthen his newly born authority and defend the Huns in the north, he ordered connecting the walls once built by the other states as well as adding some sections of his own. Thus was formed the long Qin's Great Wall which started from the east of today's Liaoning Province and ended at Lintao, Gansu Province.

In the Western Han Dynasty, the Huns became more powerful. The Han court started to build more walls on a larger scale in order to consolidate the frontier. In the west, the wall along the Hexi corridor, Yumenguan Pass, and Yangguan Pass was built. In the north, Yanmenguan Pass and Niangziguan Pass in Shanxi were set up. Many more sections of the wall extended to Yinshan Mountain and half of the ancient Silk Road was along the Han's wall.

The Northern Wei, Northern Qi and Northern Zhou Dynasties all built their own sections but on a smaller scale than the walls in the Han Dynasty. The powerful Tang Dynasty saw peace between the northern tribes and central China most of the time, so few Great Wall sections were built in this period.

The Ming Dynasty is the peak of wall building in Chinese history. The Ming suffered a lot by disturbances from minority tribes such as the Dadan, Tufan and Nuzhen. The Ming court from its first emperor to the last ceaselessly built walls in the north. The main line started from Jiuliancheng near the Yalu River in the east to the Jiayuguan Pass in the west and measured over 4,600 miles. Besides adding many more miles of its own, the Ming emperors ordered enlargement of the walls of previous dynasties into double-line or multi-line walls. For example, out of Yanmenguan Pass were added three big stone walls and 23 small stone walls. Eleven Garrisons were distributed along the main line of the wall. The countless walls, fortresses, and watch towers made the country strongly fortified. In the early Qing Dynasty, some sections of the walls were repaired and several sections were extended. This great engineering work stopped in the middle of the Qing Dynasty.

ing to its long history, natural disasters and human activities, many sections of the Great Wall are severely damaged and disappearing. Being a world-famous engineering project and witness to the rise and fall of Chinese history, the Great Wall, needs us to take immediate action to protect it!

Timbuktu

Home of the prestigious Koranic Sankore University and other madrasas, Timbuktu was an intellectual and spiritual capital and a centre for the propagation of Islam throughout Africa in the 15th and 16th centuries. Its three great mosques, Djingareyber, Sankore and Sidi Yahia, recall Timbuktu's golden age. Although continuously restored, these monuments are today under threat from desertification.

The three great mosques of Timbuktu, restored by the Qadi Al Aqib in the 16th century, bear witness to the golden age of the intellectual and spiritual capital at the end of the Askia dynasty. They played an essential part in the spread of Islam in Africa at an early period.

Timbuktu is thought to have been founded towards the end of the 5th century of the Hegira by a group of Imakcharen Tuaregs who, having wandered 250 km south of their base, established a temporary camp guarded by an old woman, Buktu. Gradually, Tim-Buktu (the place of Buktu) became a small sedentary village at the crossroads of several trade routes. Quickly converted to Islam (the two great mosques of Djingareyber and Sankore appeared during the Mandingue period), the market city of Timbuktu reached its apex under the reign of the Askia (1493-1591). It then became an important centre of Koranic culture with the University of Sankore and numerous schools attended, it is said, by some 25,000 students. Scholars, engineers and architects from various regions in Africa rubbed shoulders with wise men and marabouts in this intellectual and religious centre. Early on, Timbuktu attracted travellers from far-away countries.

Although the mosques of El-Hena, Kalidi and Algoudour Djingareye have been destroyed, three essential monuments - the mosques of Djingareyber, Sankore and Sidi Yahia - fortunately still stand as testimony to the grandeur of Timbuktu.

The Mosque of Djingareyber was built by the sultan Kankan Moussa after his return in 1325 from a pilgrimage to Mecca. Between 1570 and 1583 the Qadi of Timbuktu, Imam Al Aqib, had it reconstructed and enlarged, adding the whole southern part and the wall enclosing the graveyard situated to the west. The central minaret dominates the town and is the most visible landmark of the urban landscape. A smaller minaret on the eastern facade completes the profile of the Great Mosque which has three inner courtyards.

Like Djingareyber, the Mosque of Sankore, built during the Mandingue period, was restored by the Imam Al Aqib between 1578 and 1582. He had the sanctuary demolished and rebuilt according to the measurements of the Kaaba at Mecca, which he had taken with a rope during his pilgrimage.

The Mosque of Sidi Yahia, south of Sankore, was probably built around 1400 by the marabout Sheikh El Moktar Hamalla in anticipation of a holy man who appeared 40 years later in the person of Cherif Sidi Yahia, who was then chosen as Imam. It was restored in 1577-78 by the Imam Al Aqib. Apart from the mosques, the World Heritage site comprises 16 cemeteries and mausolea, essential elements in a religious system as, according to popular belief; they constitute a rampart that shields the city from all misfortune. The most ancient mausoleum is that of Sheikh Abul Kassim Attouaty, who died in year 936 of the Hegira (1529) and was buried 150 m west of the city with 50 ulemas and holy persons from Touat. Equally noteworthy and from the same general period are the graves of the scholar Sidi Mahmoudou, who died in year 955 of the Hegira (1547) and of Qadi Al Aqfb, the restorer of mosques, who died in year 991 of the Hegira (1583).