Tangier is built on the slopes of a chalky limestone hill. The old town (medina), enclosed by 15th-century ramparts, is dominated by a casbah, the sultan’s palace (now a museum of Moroccan art), and the Great Mosque. European quarters, whose populations have declined considerably since interrogation with Morocco in 1956, stretch to the south and west. Tangier has been the summer site of the Moroccan royal residence since 1962. An important port and trade centre, the city has excellent road and rail connections with Fes, Meknes, Rabat, and Casablanca, as well as an international airport and regular shipping services to Europe. The building trades, fishing, and textile, and carpet manufacturing supplement the city’s vibrant tourist trade.