There are many historic structures in the St. Louis area, some of them even representing the few of their kind that are still remaining in the United States. The water towers that dot the St. Louis landscape are examples of this. Out of the seven water towers that are still in existence in the entire United States, St. Louis is home to three. St. Louis is also home to many "firsts". The Eads Bridge is one of them. Built in 1874, it was the first bridge to use cantilevers and pneumatic caissons in the nation. So what is the distinction between a historic structure and a historic building? A "building" is something that is lived in or worked in. A "structure" is everything else that is built. Below is a list of some of the historic structures in the area.