Guggenheim Museum, officially Solomon R. Guggenheim Museum, major museum of modern art in New York City. Founded in 1939 as the Museum of Non-objective Art, the Guggenheim is known for its remarkable circular building (1959) with curving interior ramp designed by Frank Lloyd Wright. It holds major exhibitions, mainly of the works of contemporary artists. Its permanent collection includes, among many modern works, numerous pieces by Brancusi and Kandinsky. In 1992 the Guggenheim opened a 10-story limestone addition in the rear of the original structure and also began operating a branch in the city's SoHo district. The museum is part of the Solomon R. Guggenheim Foundation, which also controls the Peggy Guggenheim Collection in Venice. Also under the foundation's aegis is the gigantic, curving titanium-sheathed Guggenheim Museum in Bilbao, Spain, designed by Frank Gehry and inaugurated in 1997. That same year the foundation also opened a much smaller Berlin branch. From 2001 to 2008 the museum, in cooperation with Russia's Hermitage, sponsored the Guggenheim Hermitage Museum in Las Vegas, an exhibition space that featured works from both institutions.