The French engineer Gustave Eiffel designed the Eiffel Tower. The tower, arguably the most well-known monument in the world, is the tallest structure in Paris. It was completed in 1889, and it has had several hundred million visitors since it opened. A workforce of about 250 riveted in excess of 18,000 pieces of iron together to erect this long-lived landmark (it was not originally slated to be left standing), which has a structural design credited to Maurice Koechlin.