Instruct: Given a question, retrieve relevant documents that answer the question.
Query: What is the angle of the Leaning Tower of Pisa?
The height of the tower is from the ground on the low side and on the high side. The width of the walls at the base is . Its weight is estimated at . The tower has 296 or 294 steps; the seventh floor has two fewer steps on the north-facing staircase. In 1990 the tower leaned at an angle of 5.5 degrees, but following remedial work between 1993 and 2001 this was reduced to 3.97 degrees, reducing the overhang by 45 cm at a cost of £200m. It lost a further 4 cm of tilt in the two decades to 2018.
According to Cleomedes' "On the Circular Motions of the Celestial Bodies", around 240 BC, Eratosthenes, the librarian of the Library of Alexandria, calculated the circumference of the Earth in Ptolemaic Egypt. Using a scaphe, he knew that at local noon on the summer solstice in Syene (modern Aswan, Egypt), the Sun was directly overhead. (Syene is at latitude 24°05′ North, near to the Tropic of Cancer, which was 23°42′ North in 100 BC) He knew this because the shadow of someone looking down a deep well at that time in Syene blocked the reflection of the Sun on the water. He then measured the Sun's angle of elevation at noon in Alexandria by using a vertical rod, known as a gnomon, and measuring the length of its shadow on the ground. Using the length of the rod, and the length of the shadow, as the legs of a triangle, he calculated the angle of the sun's rays. This angle was about 7°, or 1/50th the circumference of a circle; taking the Earth as perfectly spherical, he concluded that the Earth's circumference was 50 times the known distance from Alexandra to Syene (5,000 stadia, a figure that was checked yearly), i.e. 250,000 stadia. Depending on whether he used the "Olympic stade" (176.4m) or the Italian stade (184.8m), this would imply a circumference of 44,100 km (an error of 10%) or 46,100 km, an error of 15%. In 2012, Anthony Abreu Mora repeated Eratosthenes's calculation with more accurate data; the result was 40,074 km, which is 66 km different (0.16%) from the currently accepted polar circumference.
The Willis Tower, built as and still commonly referred to as the Sears Tower, is a 110-story, skyscraper in Chicago, Illinois. At completion in 1973, it surpassed the World Trade Center in New York to become the tallest building in the world, a title it held for nearly 25 years; it remained the tallest building in the Western Hemisphere until the completion of a new building at the rebuilt World Trade Center site in 2014. The building is considered a seminal achievement for architect Fazlur Rahman Khan. The Willis Tower is currently the second-tallest building in the United States and the Western hemisphere – and the 16th-tallest in the world. More than one million people visit its observation deck each year, making it one of Chicago's most popular tourist destinations. The structure was renamed in 2009 by the Willis Group as a term of its lease.
Located between Tower Peak and the North Peak, the Ishpatina Canyon is one of the deepest in Ontario. The elevation of Tower Peak is 2274 feet, the bottom of the Canyon is at 1750 feet and the North Peak at 2250 feet above sea level. The canyon is nearly twice as deep as Ouimet Canyon, often considered Ontario's deepest. However, the more gradual descent into the canyon hides the fact.
Due to the steep slope on which the building is situated, it had to be specially designed out of concrete to fit into its foundations correctly. From the front, the building appears to have only three floors. However, from the rear, all of its six floors can be seen. One part of the building's foundation was made of concrete piles, and the other as a continuous foundation. Usually, these two approaches do not mix well but Horodecki somehow succeeded in overcoming this technical problem.
Just to the west from there lies the École Militaire (Military school) built from 1751, but it is to the river end of its former parade ground that lies Paris' foremost tourist attraction. The Eiffel Tower, built by Gustave Alexandre Eiffel for the 1889 Universal Exposition, averages around 6 million visitors a year.
On September 11, 2001, the structure was damaged by debris when the nearby North Tower of the World Trade Center collapsed. The debris also ignited fires, which continued to burn throughout the afternoon on lower floors of the building. The building's internal fire suppression system lacked water pressure to fight the fires, and the building collapsed completely at , according to FEMA, while the 2008 NIST study placed the final collapse time at . The collapse began when a critical internal column buckled and triggered structural failure throughout, which was first visible from the exterior with the crumbling of a rooftop penthouse structure at 5:20:33 pm. The collapse made the old 7 World Trade Center the first tall building known to have collapsed primarily due to uncontrolled fires, and at the time, the only steel skyscraper in the world to have collapsed due to fire.
The Eiffel Tower, by far Paris' most famous monument, averages over six million visitors per year and more than 200 million since its construction.
Oak says that well-known western authorities on architecture including Ernest Binfield Havell, Mrs. Kenoyer and William Wilson Hunter have written that the Taj Mahal is built in the Hindu temple style, asserting that Havel says the plan of the ancient Hindu temple of Java, the Prambanan, is identical with that of the Taj Mahal. Also, he argues out that the octagonal shape of the Taj Mahal has a special Hindu significance, because Hindus alone have special names for the eight directions and the celestial guards assigned to them. He argues that the finial of the Taj Mahal is a trishula with a Kalasha, holding two bent mango leaves and a coconut, which is a sacred Hindu motif.
The Colosseum or Coliseum ( ), also known as the Flavian Amphitheatre (Latin: "Amphitheatrum Flavium"; Italian: "Anfiteatro Flavio" or "Colosseo" ), is an oval amphitheatre in the centre of the city of Rome, Italy. Built of travertine, tuff, and brick-faced concrete, it is the largest amphitheatre ever built. The Colosseum is situated just east of the Roman Forum. Construction began under the emperor Vespasian in AD 72, and was completed in AD 80 under his successor and heir Titus. Further modifications were made during the reign of Domitian (81–96). These three emperors are known as the Flavian dynasty, and the amphitheatre was named in Latin for its association with their family name "(Flavius)".
Constructed from 1887–1889 as the entrance to the 1889 World's Fair, it was initially criticised by some of France's leading artists and intellectuals for its design, but it has become a global cultural icon of France and one of the most recognisable structures in the world. The Eiffel Tower is the most-visited paid monument in the world; 6.91 million people ascended it in 2015.
The entire monument is made of Pentelic marble, from Mt. Pentelikon, 18.2 km northeast of the arch. Pentelic marble was used for the Parthenon and many other notable structures in Athens, although its quality can vary significantly. The marble used for the arch is of a lower grade that had more inclusions than that used in the best Athenian buildings. The arch was constructed without cement or mortar from solid marble, using clamps to connect the cut stones. It is 18m high, 13.5m wide, and 2.3m in depth. Its design is fully symmetrical from front to back and side to side.
Blackpool Tower is a tourist attraction in Blackpool, Lancashire, England, which was opened to the public on 14 May 1894. Inspired by the Eiffel Tower in Paris, it is tall and is the 120th tallest freestanding tower in the world. Blackpool Tower is also the common name for Tower buildings, an entertainment complex in a red-brick three-storey block comprising the tower, the ground floor aquarium and cafeteria, Tower Circus, the Tower Ballroom and roof gardens that was designated a Grade I listed building in 1973.
Proponents of World Trade Center controlled demolition theories allege that 7 World Trade Center—a 47-story skyscraper that stood across Vesey Street north of the main part of the World Trade Center site—was intentionally destroyed with explosives. Unlike the Twin Towers, 7 World Trade Center was not hit by a plane, although it was hit by debris from the Twin Towers and was damaged by fires which burned for seven hours, until it collapsed completely at about 5:20 p.m. on the evening of September 11 (a new building has been erected on the site of the old and opened in May 2006). Several videos of the collapse event exist in the public domain, thus enabling comparative analysis from different angles of perspective. Proponents typically say the collapse of 7 World Trade Center was not mentioned in the 9/11 Commission Report and that the federal body charged with investigating the event, NIST, required seven years to conduct its investigation and issue a report.
In 1508 Pope Julius II succeeded in getting the Florentine sculptor Michelangelo (1475-1564) to agree to continue the decorative scheme of the Sistine Chapel. The Sistine Chapel ceiling was constructed in such a way that there were twelve sloping pendentives supporting the vault that formed ideal surfaces on which to paint the Twelve Apostles. Michelangelo soon devised an entirely different scheme, far more complex both in design and in iconography. The scale of the work, which he executed single handed except for manual assistance, was titanic and took nearly five years to complete.
On 25 January 1504, when the sculpture was nearing completion, Florentine authorities had to acknowledge there would be little possibility of raising the more than six-ton statue to the roof of the cathedral. They convened a committee of 30 Florentine citizens that comprised many artists, including Leonardo da Vinci and Sandro Botticelli, to decide on an appropriate site for "David". While nine different locations for the statue were discussed, the majority of members seem to have been closely split between two sites. One group, led by Giuliano da Sangallo and supported by Leonardo and Piero di Cosimo, among others, believed that, due to the imperfections in the marble, the sculpture should be placed under the roof of the Loggia dei Lanzi on Piazza della Signoria; the other group thought it should stand at the entrance to the Palazzo della Signoria, the city's town hall (now known as Palazzo Vecchio). Another opinion, supported by Botticelli, was that the sculpture should be situated on or near the cathedral. In June 1504, "David" was installed next to the entrance to the Palazzo Vecchio, replacing Donatello's bronze sculpture of "Judith and Holofernes", which embodied a comparable theme of heroic resistance. It took four days to move the statue the half mile from Michelangelo's workshop into the Piazza della Signoria. Later that summer the sling and tree-stump support were gilded, and the figure was given a gilded loin-garland.
On November 15, Pike recorded the first sight of the distant mountain he called "Grand Peak". It has since been called Pikes Peak in his honor. Pike tried to climb the peak, hoping to get a view of the surrounding area to record on maps, the 14,000-foot summit. Pike's group ascended a lesser summit nearby—likely Mount Miller, which was named for Theodore Miller, one of the soldiers who accompanied Pike. With winter threatening, Pike pressed onward up the Arkansas, and on December 7 the party reached Royal Gorge, a spectacular canyon on the Arkansas at the base of the Rocky Mountains.
In early November 1806, Pike and his team sighted and tried to climb to the summit of the peak later named after him (Pikes Peak). They made it as far as Mt. Rosa, located southeast of Pikes Peak, before giving up the ascent in waist-deep snow. They had already gone almost two days without food.
Ostankino Tower (, "Ostankinskaya telebashnya") is a television and radio tower in Moscow, Russia, owned by the Moscow branch of unitary enterprise Russian TV and Radio Broadcasting Network. Standing , Ostankino was designed by Nikolai Nikitin. It is currently the tallest free-standing structure in Europe and 11th tallest in the world. Between 1967 and 1976 it was the tallest in the world. The tower was the first free-standing structure to exceed in height. Ostankino was built to mark the 50th anniversary of the October Revolution. It is named after the surrounding Ostankino district of Moscow.
In 1508 Pope Julius II succeeded in getting the sculptor Michelangelo to agree to continue the decorative scheme of the Sistine Chapel. The Sistine Chapel ceiling was constructed in such a way that there were twelve sloping pendentives supporting the vault that formed ideal surfaces on which to paint the Twelve Apostles. Michelangelo, who had yielded to the Pope's demands with little grace, soon devised an entirely different scheme, far more complex both in design and in iconography. The scale of the work, which he executed single handed except for manual assistance, was titanic and took nearly five years to complete.
The address of this building was 2 World Trade Center with the WTC complex having its own ZIP code of 10048. It was destroyed along with the North Tower (1 World Trade Center) in the September 11 attacks. The South Tower was the second tower to be struck, at 9:03 a.m., and the first tower to collapse, at 9:59 a.m. Of the 2,977 victims killed in the attacks, 614 were in or above the South Tower impact zone. At the National September 11 Memorial & Museum, the southern pool marks the spot where the South Tower stood.
The tower reached the height of around 28 meters and consists of eight levels. It had square shaped platform and 64 niches on the octagonal frame. It was slightly leaning, although the angle was less compared to the Leaning Tower of Pisa.
Huzhu Pagoda () is a Chinese Pagoda located on Tianmashan Hill in the Songjiang District of Shanghai. It is known for its leaning angle, surpassing that of the Leaning Tower of Pisa.
The leaning tower illusion is a visual illusion seen in a pair of identical images of the Leaning Tower of Pisa photographed from below. Although the images are duplicates, one has the impression that the tower on the right leans more, as if photographed from a different angle. The illusion was discovered by Frederick Kingdom, Ali Yoonessi and Elena Gheorghiu at McGill University, and won first prize in the Best Illusion of the Year Contest 2007.
The Leaning Tower of Pisa () or simply the Tower of Pisa ("Torre di Pisa" ) is the "campanile", or freestanding bell tower, of the cathedral of the Italian city of Pisa, known worldwide for its unintended tilt. The tower is situated behind the Pisa Cathedral and is the third oldest structure in the city's Cathedral Square ("Piazza del Duomo"), after the cathedral and the Pisa Baptistry.