The British Museum opened in 1759 and houses artifacts from Sir Hans Sloane's vast collection. It has been open since then except during World War I when it closed for safety. In 2000, architect Norman Foster renovated the central part with a glass ceiling. The London Eye is a large Ferris wheel situated on the Thames that offers panoramic views of London in about 30 minutes. Norman Foster also designed City Hall with a distinctive bulbous shape and glass walls. Tate Modern is housed in a former power station and is one of London's most visited museums, known for displaying modern art.