Housed in the society's three-building headquarters complex, the National Georgraphic Society Explorers Hall was opened in 1964. It occupies the ground floor of a 10-story marble and glass structure designed by Edward Durell Stone, architect of the Kennedy Center. Overhauled in 2001, the museum at Explorers Hall now showcases 3-D models, from its permanent collection. Changing exhibits on cultural, geographic or scientific topics, generally feature photographs and discoveries made by photographers and researchers who work for the National Geographic Society.