The Eiffel Tower is an iron tower built on the Champ de Mars beside the River Seine in Paris. The tower has become a global icon of France and is one of the most recognizable structures in the world.

Introduction

The Parisian landmark is the tallest structure in Paris and one of the most recognized structures in the world and is named after its designer, engineer Gustave Eiffel. 6,719,200 people visited the tower in 2006 and more than 200,000,000 since its construction. This makes the tower the most visited paid monument in the world. Including the 24 m (79 ft) antenna, the structure is 325 m (1,063 ft) high (since 2000), which is equivalent to about 81 levels in a conventional building.

When the tower was completed in 1889 it replaced the Washington Monument as the world's tallest structure — 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 structure of the Eiffel Tower weighs 7,300 tons. Depending on the ambient temperature the top of the tower may shift away from the sun by up to 18 cm (7 in) due to 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 first and second levels are accessible by stairs and lifts. A ticket booth at the south tower base sells tickets to use the stairs which begin at that location. At the first platform the stairs continue up from the east tower and the third level summit is only accessible by lift. Once you are on the first or second platform the stairs are open for anyone to ascend or descend regardless of whether you have purchased a lift ticket or stair ticket. The actual count of stairs includes 9 steps to the ticket booth at the base, 328 steps to the first level, 340 steps to the second level and 18 steps to the lift platform on the second level. When exiting the lift at the third level 15 more steps exist to ascend to the upper observation platform. The step count is printed periodically on the side of the stairs to give an indication of progress. The majority of the ascent allows for an unhindered view of the area directly beneath and around the tower except during brief stretches of the stairway that are enclosed.

Maintenance of the tower includes applying 50 to 60 tons of paint every seven years to protect it from rust. In order to maintain a uniform appearance to an observer on the ground, three separate tones of paint are used on the tower, with the darkest tone on the bottom, and the lightest at the top. On occasion the colour of the paint is changed — the tower is currently painted a shade of brownish-grey. On the first floor there are interactive consoles hosting a poll for the colour to use for a future session of painting. The co-architects of the Eiffel Tower are Emile Nouguier, Maurice Koechlin and Stephen Sauvestre.

Background

The structure was built between 1887 and 1889 as the entrance arch for the Exposition Universelle, a World's Fair marking the centennial celebration of the French Revolution. Eiffel originally planned to build it in Barcelona, for the Universal Exposition of 1888, but those responsible at the Barcelona city hall thought it was a strange construction, and expensive, which did not fit into 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 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 puddled 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. Yet because Eiffel took safety precautions including use of movable stagings, guard-rails and screens, only one man died.

The tower was met with resistance from the public when it was built, with many calling it an eyesore. (Novelist Guy de Maupassant — who claimed to hate the tower — supposedly ate lunch at the Tower's restaurant every day. When asked why, he answered that it was the one place in Paris where you couldn't see the Tower.) Today, it is widely considered to be a striking piece of structural art.

One of the great Hollywood movie clichés is that the view from a Parisian window always includes the tower. In reality, since zoning restrictions limit the height of most buildings in Paris to 7 stories, only the very few taller buildings have a clear view of the tower.

Eiffel had a permit for the tower to stand for 20 years, meaning it would have had to be dismantled in 1909, when its ownership would revert to the City of Paris. The City had planned to tear it down (part of the original contest rules for designing a tower was that it could be easily demolished) but as the tower proved valuable for communication purposes, it was allowed to remain after the expiration of the permit. The military used it to dispatch Parisian taxis to the front line during the First Battle of the Marne, and it therefore became a victory statue of that battle.

Shape of the tower

At the time the tower was built many people were shocked by its daring shape. Gustave Eiffel was criticised for the design and accused of trying to create something artistic, or inartistic according to the viewer, without regard to engineering. Eiffel and his engineers, as renowned bridge builders however, understood the importance of wind forces and knew that if they were going to build the tallest structure in the world they had to be certain it would withstand the wind. In an interview reported in the newspaper Le Temps, Eiffel said:
" Now to what phenomenon did I give primary concern in designing the Tower? It was wind resistance. Well then! I hold that the curvature of the monument's four outer edges, which is as mathematical calculation dictated it should be (...) will give a great impression of strength and beauty, for it will reveal to the eyes of the observer the boldness of the design as a whole. "

- translated from the French newspaper Le Temps of 14 February 1887

The shape of the tower was therefore determined by mathematical calculation involving wind resistance. Several theories of this mathematical calculation have been proposed over the years, the most recent is a nonlinear integral differential equation based on counterbalancing the wind pressure on any point on the tower with the tension between the construction elements at that point. That shape is exponential.

Installations

Since the beginning of the 20th century, the tower has been used for radio transmission. Until the 1950s, an occasionally modified set of antenna wires ran from the summit to anchors on the Avenue de Suffren and Champ de Mars. They were connected to long-wave transmitters in small bunkers; in 1909, a permanent underground radio centre was built near the south pillar and still exists today. On 20 November 1913 the Paris Observatory, using the Eiffel Tower as an antenna, exchanged sustained wireless signals with the United States Naval Observatory which used an antenna in Arlington, Virginia.

The object of the transmissions was to measure the difference in longitude between Paris and Washington, DC.

The tower has two restaurants: Altitude 95, on the first floor (95 m, 311 ft, above sea level); and the Jules Verne, an expensive gastronomical restaurant on the second floor, with a private lift. This restaurant has one star in the Michelin Red Guide. In January 2007 a new multi-Michelin star chef Alain Ducasse was brought in to run Jules Verne.

The uppermost observation deck, with a height of 275 metres, is the highest area of an architectural structure in the European Union open for the public.

The passenger lifts from ground level to the first level are operated by cables and pulleys driven by massive water-powered pistons. As they ascend the inclined arc of the legs, the elevator cabins tilt slightly, but with a slight jolt, every few seconds in order to keep the floor nearly level. The elevator works are on display and open to the public in a small museum located in one of the four tower bases, and waiting queues are much shorter than those for the tower ascent.

Events

• On 10 September 1889 Thomas Edison visited the tower. He signed the guestbook with the following message - " To M Eiffel the Engineer the brave builder of so gigantic and original specimen of modern Engineering from one who has the greatest respect and admiration for all Engineers including the Great Engineer the Bon Dieu, Thomas Edison. "
• In 1902, the tower was struck by lightning (see photo below). 100 m (330 ft) of the top had to be reconstructed and the damaged lights illuminating the tower had to be replaced.
• Father Theodor Wulf in 1910 took observations of radiant energy radiating at the top and bottom of the tower, discovering at the top more than was expected, and thereby detecting what are today known as cosmic rays.
• In 1925, the con artist Victor Lustig twice "sold" the tower for scrap metal.
• In 1930, the tower lost the title of the world's tallest structure when the Chrysler Building was completed in New York City.
• From 1925 to 1934, illuminated signs for Citroën adorned three of the tower's four sides, making it the tallest advertising space in the world at the time.
• Upon the Nazi occupation of Paris in 1940, the lift cables were cut by the French so that Adolf Hitler would have to climb the steps to the summit. The parts to repair them were allegedly impossible to obtain because of the war. In 1940 Nazi soldiers had to climb to the top to hoist the swastika, but the flag was so large it blew away just a few hours later, and it was replaced by a smaller one. When visiting Paris, Hitler chose to stay on the ground. It was said that Hitler conquered France, but did not conquer the Eiffel Tower. A Frenchman scaled the tower during the German occupation to hang the French flag. In August 1944, when the Allies were nearing Paris, Hitler ordered General Dietrich von Choltitz, the military governor of Paris, to demolish the tower along with the rest of the city. Von Choltitz disobeyed the order. The lifts of the Tower were working normally within hours of the Liberation of Paris.
• On 3 January 1956, a fire damaged the top of the tower.
• In 1957 the present radio antenna was added to the top.
• In the 1980s an old restaurant and its supporting iron scaffolding midway up the tower was dismantled; it was purchased and reconstructed on St. Charles Avenue in New Orleans, Louisiana by entrepreneurs John Onorio and Daniel Bonnot, originally as the Tour Eiffel Restaurant, known more recently as the Red Room. The restaurant was re-assembled from 11,000 pieces that crossed the Atlantic in a 40-foot cargo container.
• In 1985's James Bond action/adventure film A View to a Kill, Sir Roger Moore as James Bond chases May Day played by actress Grace Jones at the Eiffel Tower. She parachuted from the tower. The video of the film's theme, performed by the group Duran Duran, also included several scenes of the band staged on the tower.
• On New Year's Eve 2000, the Eiffel Tower played host to Paris' Millennium Celebration. Fireworks exploded from the whole length of the tower in a spectacular display.
• In 2000, flashing lights and four high-power searchlights were installed on the tower. Since then the light show has become a nightly event. The searchlights on top of the tower make it a beacon in Paris' night sky.
• The tower received its 200,000,000th guest of all-time in 2002.


• At 19:20 on 22 July 2003, a fire occurred at the top of the tower in the broadcasting equipment room. The entire tower was evacuated; the fire was extinguished after 40 minutes, and there were no reports of injuries.
• Since 2004, the Eiffel Tower has hosted an ice skating rink on the first floor during the winter period. Skating is free in Paris.

At Night

At night the Eiffel Tower is entirely lit up a gold-yellow color. At every hour that it is lit up, from the hour to five minutes after the hour it puts on a sparkling show.