page_title: Eiffel Tower
section_title: Material
hierarchical_section_title: Eiffel Tower / Design / Material
caption_attribution_description: Français&#160;: Vue de la Tour Eiffel, de dessous.English: Looking up the center of the Eiffel Tower.
context_page_description: The Eiffel Tower is a wrought-iron lattice tower on the Champ de Mars in Paris, France. It is named after the engineer Gustave Eiffel, whose company designed and built the tower.
  Constructed from 1887 to 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 tower is 324 metres tall, about the same height as an 81-storey building, and the tallest structure in Paris. Its base is square, measuring 125 metres on each side. During its construction, the Eiffel Tower surpassed the Washington Monument to become the tallest man-made structure in the world, a title it held for 41 years until the Chrysler Building in New York City was finished in 1930. It was the first structure to reach a height of 300 metres. Due to the addition of a broadcasting aerial at the top of the tower in 1957, it is now taller than the Chrysler Building by 5.2 metres.
context_section_description: The puddled iron (wrought iron) of the Eiffel Tower weighs 7,300 tons, and the addition of lifts, shops and antennae have brought the total weight to approximately 10,100 tons. As a demonstration of the economy of design, if the 7,300 tons of metal in the structure were melted down, it would fill the square base, 125 metres (410 ft) on each side, to a depth of only 6.25 cm (2.46 in) assuming the density of the metal to be 7.8 tons per cubic metre. Additionally, a cubic box surrounding the tower (324 m x 125 m x 125 m) would contain 6,200 tons of air, weighing almost as much as the iron itself. 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.
caption: The Eiffel Tower from below
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