Originally built during the Liao Dynasty in 996, Niujie is Beijing's oldest and largest mosque. It sits at the center of the Muslim quarter and mimics a Chinese temple from the outside, with its hexagonal wooden structure. When the mosque was built, only traditional Chinese architecture was allowed in the capital. An exception was made for the Arabic calligraphy that decorates many of the mosque's walls and inner sanctums. The interior arches and posts are inscribed with Koranic verse, and a special moon tower helps with determining the lunar calendar. The Spirit Wall stands opposite the main entrance and is meant to prevent ghosts from entering the mosque. This wall is covered with carved mural works on the premise that ghosts can't turn sharp corners. Two dark tombs with Chinese and Arabic inscriptions are kept in one of the small courtyards. They belong to two Persian imams (the prayer leaders of a mosque) who came to preach at the mosque in the 13th and 14th centuries. Because Muslims
must pray in the direction of Mecca, which is westward, the main prayer hall opens onto the east. At the rear of the complex is a minaret from which a muezzin calls the faithful to prayer. From this very tower, imams measure the beginning and end of Ramadan, Islam's month of fasting and prayer. Ramadan begins when the imam sights the new moon, which appears as a slight crescent.
The hall, which is open only to Muslims, can fit up to 1,000 worshippers. All visitors must wear long trousers or skirts and keep their shoulders covered. It's most convenient to get to the mosque by taxi. If you want to take the subway, it's about a 10-minute walk from Line 4's Caishikou station.