Tourism in Gibraltar constitutes one of the British Overseas Territory's most important economic pillars, alongside financial services and shipping. Gibraltar's main attractions are the Rock of Gibraltar and its resident population of Barbary macaques (or apes), the territory's military heritage, duty-free shopping, casinos and marinas. Although the population of Gibraltar numbers only some 30,000 people, the territory recorded nearly 12 million visits in 2011, giving it one of the highest tourist-to-resident ratios in the world.