The Barbary Macaques are considered by many to be the top tourist attraction in Gibraltar. The most popular troop is that of Queen's Gate at The Apes' Den, where people can get especially close to the monkeys. They will often approach and sometimes climb onto people, as they are used to human interaction. Nevertheless, they are still wild animals and will bite if frightened or annoyed.

The Barbary Macaques' contact with large numbers of tourists was causing the integrity of their social groups to break down, as they began to become dependent on humans. This induced the monkeys' urge to foray into the town, resulting in damages to personal property such as buildings, clothing and vehicles. For this reason, feeding the macaques in Gibraltar is now an offence punishable by law. Anyone caught feeding the monkeys will incur a penalty fine of up to £500.

http://en.wikipedia.org/wiki/Gibraltar_Barbary_Macaques