Jerusalem's architecture is a mixture of old and new. The Old City contains architectural examples from each major period in the city's history. Many ancient historical sites and places of worship stand near modern shopping centers and industrial zones. Architecture from the late 1800s and early 1900s shows European influences. Usefulness rather than style characterizes new apartment buildings constructed by the government as housing for immigrants. Many buildings, old and new, have matching exteriors because all construction is required to be faced with a cream-colored limestone called Jerusalem stone, produced by nearby quarries.