Seattle Center Grounds photograph collection, April 1963

The Seattle World's Fair, also known as the Century 21 Exposition, was open from April 21, 1962, to October 21, 1962. Close to ten million people visited the World's Fair in that six-month period. The fairground buildings were built in a relatively short period of time and more than half were torn down after the fair, including the information booth and totem pole. The buildings that remained were transformed into popular tourist attractions as part of Seattle Center, which officially opened on June 1, 1963. The United States Science Pavilion became the Pacific Science Center. The Washington State Coliseum became the Seattle Center Coliseum sporting venue (later renamed Key Arena). Other attractions, including two repertory theaters and a museum, have been added over the years. The Space Needle remains as a centerpiece of Seattle Center and a defining symbol of the Seattle skyline.