Apes' Den, located within the Upper Rock Nature Reserve in Gibraltar, is famous for its Barbary macaques, the only wild monkey population in Europe. Visitors can observe these primates in their natural habitat, offering a unique wildlife experience. Accessibility varies; while some areas are easily reached, others involve steep climbs. Solo exploration is possible, but guided tours offer deeper insights into the macaques' behavior and the reserve's ecology. Summer can be very hot, and winter brings occasional rain, making spring and fall ideal visiting times. The cost to enter the Upper Rock Nature Reserve is approximately £13 per adult, and a typical visit to Apes' Den lasts between 1 to 2 hours, though exploring the entire reserve requires more time. Remember to avoid feeding the monkeys, as it's both harmful to them and illegal.