Set atop the city's tallest coastal promontory, the kasbah has served as Tangier's military and political center since the Roman era. Within its walls, the former royal palace, or Dar El Makhzen (tel. 0539/932097; Sun-Mon and Wed-Thurs 9am-12:30pm and 3-5:30pm, Fri 9-11:30am; admission 10dh), houses a museum of mosaics from the Roman city of Volubilis, as well as a fine selection of Moroccan crafts. A room dedicated to Fes includes some superbly bound manuscripts with exquisite calligraphy, as well as examples of the city's famous ceramics. Other regions and cities are also represented, while the building itself is a display of Morocco's renowned zellij, hand-carved stucco plasterwork, and painted ceilings.
Just south of the kasbah, in the medina proper on rue Amrah, is Sidi Hosni, former home to "poor little rich girl" Barbara Hutton. Sidi Hosni is constructed from seven separate homes that had housed during their time both a Moroccan saint and the writer Walter Harris; Hutton, the Woolworths heiress, lived here from 1947 to 1975. The three-time princess by marriage (the only one of her seven husbands not to hold a title was Cary Grant) styled herself as the princess of Tangerine society. Her parties were legendary -- she once had 30 camels transported from the desert to stand as a guard of honor -- and typical of the expat decadence seen in 1950s and 1960s Tangier. True to princess form, she even convinced the mayor of Tangier into widening the kasbah's gates so that her Rolls-Royce could pass through them.
There's a great view of the Bay of Tangier and the Straits of Gibraltar just outside the kasbah's Bab Bhar gate. If you have time, take a stroll to Cafe Hafa, off rue Assad ibn el Forrat, west of the kasbah. The aging, terraced cafe looks out across the Straits of Gibraltar and is a magical, tranquil place to enjoy the sea breeze and sip a mint tea or two. On a clear day, you can even make out the Rock of Gibraltar.