The Roman Coliseum

The Colosseum or Roman Coliseum, originally the Flavian Amphitheatre is an elliptical amphitheatre in the center of the city of Rome, Italy, the largest ever built in the Roman Empire. It is one of the greatest works of Roman architecture and Roman engineering. Occupying a site just east of the Roman Forum, its construction started between 70 and 72 AD under the emperor Vespasian and was completed in 80 AD under Titus, with further modifications being made during Domitian's reign (81–96). The name "Amphitheatrum Flavium" derives from both Vespasian's and Titus's family name Capable of seating 50,000 spectators, the Colosseum was used for gladiatorial contests and public spectacles. As well as the gladiatorial games, other public spectacles were held there, such as mock sea battles, animal hunts, executions, re-enactments of famous battles, and dramas based on Classical mythology. The building ceased to be used for entertainment in the early medieval era. It was later reused for such purposes as housing, workshops and quarters for a religious order, a fortress, a quarry, and a Christian shrine. It has been estimated that about 500,000 people and over a million wild animals died in the Colosseum games. Although in the 21st century it stays partially ruined due to damage caused by devastating earthquakes and stone-robbers, the Colosseum is an iconic symbol of Imperial Rome and its breakthrough achievements in earthquake engineering. It is one of Rome's most popular tourist attractions and still has close connections with the Roman Catholic Church, as each Good Friday the Pope leads a torchlight "Way of the Cross" procession around the various levels of the amphitheatre. The Colosseum is also depicted on the Italian version of the five-cent euro coin. (Source:http://en.wikipedia.org/wiki/Colosseum)

The Eiffel Tower

The Eiffel Tower is an iron tower built on the Champ de Mars beside the Seine River in Paris. The tower has become a global icon of France and is one of the most recognizable structures in the world. Named after its designer, engineer Gustavo Eiffel, the Eiffel Tower is the tallest building in Paris. More than 200,000,000 people have visited the tower since its construction in 1889, including 6,719,200 in 2006, making it the most visited paid monument in the world. Including the 24 m (79 ft) antenna, the structure is 324 m (1,063 ft) high (since 2000), which is equivalent to about 81 levels in a conventional building. At the time of completion in 1889, it was the world's tallest tower — a title it retained until 1930 when New York City's Chrysler Building (319 m — 1,047 ft tall) was completed. The tower is now the fifth-tallest structure in France and the tallest structure in Paris, with the second-tallest being the Tour Montparnasse (210 m — 689 ft), although that will soon be surpassed by Tour AXA (225.11 m — 738.36 ft). The metal structure of the Eiffel Tower weighs 7,300 tones while the entire structure including non-metal components is approximately 10,000 tones. Depending on the ambient temperature, the top of the tower may shift away from the sun by up to 18 cm (7 in) because of thermal expansion of the metal on the side facing the sun. The tower also sways 6–7 cm (2–3 in) in the wind. The structure was built between 1887 and 1889 as the entrance arch for the Exposition Universally, a World's Fair marking the centennial celebration of the French Revolution. Eiffel originally planned to build the tower in Barcelona, for the Universal Exposition of 1888, but those responsible at the Barcelona city hall thought it was a strange and expensive construction, which did not fit into the design of the city. After the refusal of the Consistory of Barcelona, Eiffel submitted his draft to those responsible for the Universal Exhibition in Paris, where he would build his tower a year later, in 1889. The tower was inaugurated on 31 March 1889, and opened on 6 May. Three hundred workers joined together 18,038 pieces of puddle iron (a very pure form of structural iron), using two and a half million rivets, in a structural design by Maurice Koechlin. The risk of accident was great, for unlike modern skyscrapers the tower is an open frame without any intermediate floors except the two platforms. However, because Eiffel took safety precautions, including the use of movable staging, guard-rails and screens, only one man died. (Source:http://en.wikipedia.org/wiki/Eiffel_Tower)