La Cabaña is an 18th-century fortress complex and the third-largest in the Americas, located on the elevated eastern side of Havana harbor entrance. Built between 1763 and 1774 after the British occupation of Havana, it spans 10 hectares. You can spend at least half a day exploring its rich attractions including the Museum of Fortifications and Arms, Museo de Comandancia del Che, and a cigar shop containing the world's longest cigar. The fortress hosts the famous cañonazo ceremony every night at 9pm.