The Eiffel Tower

The Eiffel Tower, or French Tour Eiffel, is an important landmark in Paris and is one of the finest works of technology in building-construction history.  When the French government organized the 1889 International Exhibition to celebrate the centenary of the Revolution, a design competition was held for a suitable monument.  More than 100 designs were submitted, and Gustav Eiffel, a bridge engineer recognized by the Century Committee, agreed.  Eiffel’s concept of a 300-meter (984-foot) tower is almost entirely made of open mesh and iron.  When completed, the tower looked like the entrance to the exhibition.
Nothing is built as tall as the Eiffel Tower.  It was twice the height of St. Peter’s Sphere in Rome or the Great Pyramid of Giza.  In stark contrast to such ancient monuments, the tower was built in about two years (1887-89) with a small workforce.  Utilizing his advanced knowledge of the behavior of metal arches and metal truss models under load, the Eiffel created a lightweight, airy but sturdy structure that revolutionized civil engineering and architectural design.  When it opened to the public on May 15, 1889, it was aesthetically pleasing.
The Eiffel Tower is perched on four lattice-girder towers, knocking it inwards to form a single large vertical tower.  When they curve inwards, the holes are connected to each other like magic on two levels where visitors can see the stage.  In contrast, the four semi-circular arches at the base of the tower are purely aesthetic elements that do not serve a structural function.  Because of their unique shape, partly due to engineering considerations and partly because of Eiffel’s artistic sense, the drillmen needed elevators to climb the curve.  Glass-lanterns, designed by Otis Elevator Company in the United States, became a key feature of the building and helped establish it as one of the world’s leading tourist attractions.
The tower is 300 meters (984 feet) high.  It is located on a base 5 m (17 ft) high, with a TV antenna at the top of the tower giving it an altitude of 324 m (1,063 ft).  Until the construction of the Chrysler Building in New York City in 1929, the Eiffel Tower was the tallest structure in the world.