This is Beijing's largest mosque and the spiritual center for the city's estimated 200,000 Muslims. Built in 996, the complex looks more Eastern than Middle Eastern, with sloping tile roofs similar to those found in Buddhist temples. Halls are noticeably free of idols, however. A small courtyard on the south side contains the tombs and original gravestones of two Arab imams who lived here in the late 13th century. The main prayer hall is ghostly quiet except on Friday, the traditional day of worship.