March 31, 1889 – The Eiffel Tower is officially opened.
The Eiffel Tower is a wrought iron lattice structure on the Champ de Mars in Paris, France. It is named after the engineer Gustave Eiffel, whose company designed and built the tower. Constructed in 1889 as the entrance to the 1889 World’s Fair, it was initially criticized by some of France’s leading artists and intellectuals for its design, but has become a global cultural icon of France and one of the most recognizable structures in the world. The tower is the tallest structure in Paris and the most-visited paid monument in the world: 6.98 million people ascended it in 2011. The tower received its 250 millionth visitor in 2010.
The tower is 324 meters (1,063 ft) tall, about the same height as an 81-story building. Its base is square, 125 meters (410 ft) on a 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 built in 1930. Due to the addition of the aerial at the top of the tower in 1957, it is now taller than the Chrysler Building by 5.2 metres (17 ft). Not including broadcast aerials, it is the second-tallest structure in France, after the Millau Viaduct.
The tower has been used for making radio transmissions since the beginning of the 20th century. Until the 1950s, sets of aerial wires ran from the cupola to anchors on the Avenue de Suffren and Champ de Mars. These were connected to longwave transmitters in small bunkers. In 1909, a permanent underground radio centre was built near the south pillar, which still exists today. On November 20, 1913, the Paris Observatory, using the Eiffel Tower as an aerial, exchanged wireless signals with the United States Naval Observatory, which used an aerial in Arlington, Virginia. The object of the transmissions was to measure the difference in longitude between Paris and Washington, D.C. Today, radio and television signals are transmitted from the Eiffel Tower.
On May 5, 1939, France issued a semi-postal stamp, 90-centimes + 50 centimes, commemorating the 50th anniversary of the tower (Scott No. B85):