In 1904, St. Louis hosted the World's Fair. This World's Fair was officially known as the Louisiana Purchase Exposition because it was also celebrating the Centennial of the Louisiana Purchase that happened in 1804. The Fair was opened on April 30, 1904 and ran eight months and the last day of the Fair was December 1, 1904. It was estimated that over 20 million visitors had come to the 1904 World's Fair.
The World's Fair was held in Forest Park which had been established in 1876 and at the time was covered in swamps and forest and the polluted River Des Peres meandered through it. The park was chosen as the fair's site in 1901. It took 10,000 workmen and three years to tranform the wilderness that Forest Park was, into the the splendor of the fairgrounds. Those fairgrounds included 1,200 acres of newly redesigned landscape which featured gardens, numerous lakes and other bodies of water, 1,500 beautiful structures and several grand palaces.
Most of the grand buildings of the Fair were designed to be temporary structures being made out of a plaster of Paris and hemp fiber mixture placed on wood frames. The Art Palace, located in what is now the St. Louis Art Museum, is one of only two buildings used by the Fair that were built to be permanent structures. The other building was located on the then, newly built campus of Washington University and was used as the Administration building. It is now the iconic Brookings Hall. The Grand Basin was recently restored to its original World's Fair design for the 2004 celebration of the 1904 World's Fair Centennial is located at the bottom of Art Hill in fromt of the St. Louis Art Museum. The only other structure to remain from the 1904 World's Fair is the Open Flight bird cage located in the St. Louis Zoo.
As part of the agreement for the World's Fair to be held in Forest Park, the organizers had to redevelop the site into an organized park after the completion of the Fair. The St. Louis Zoo was developed around the Open Flight Bird Cage in 1913 and the Art Palace was given to the city for the St. Louis Art Museum. In remembrance of the Louisiana Purchase Exposition, the Jefferson Memorial was built which now houses the Missouri History Museum. Today, many artifacts from the 1904 World's Fair are on display at the Missouri History Museum.
The Missouri History Museum has a great permanent exhibit featuring the 1904 World's Fair - Louisiana Purchase Exposition.Missouri Historical Society Website, Missouri History Museum 1904 World's Fair Website