Berlin’s museums authority says one of the city’s best-known cultural treasures, the Pergamon Altar, will be shut to visitors for up to five years from September for restoration work on the building that houses it. The altar, decorated with a marble frieze, was built between 197 and 156 B.C. in the present-day Turkish town of Bergama. It’s the centerpiece of Berlin’s Pergamon Museum. The central hall that contains the altar will close Sept. 29, and likely won’t reopen until 2019.