Arequipa is the capital of the colonial era of the Arequipa region in Peru. It is surrounded by 3 volcanoes and has baroque buildings constructed of sillar, a white volcanic stone. In its historic center, is the Plaza de Armas, an imposing main square, and to the north of it is the 17th-century neoclassical Cathedral Basilica, which houses a museum where works of art and religious objects are exhibited.