Gunung Mulu National Park Sarawak

Arguably the most impressive destination in Borneo, World Heritage–listed Gunung Mulu National Park manages to pack some of the planet's most incredible (and accessible) caves, brilliant old-growth tropical rainforest and out-and-out oddities such as the Pinnacles formation on Mt Api into its modest 529 sq km. The park is an enthralling and magnificent example of Borneo's natural heritage. Pride of place goes to the amazing cave systems, part of a karst landscape that also influences the area's biological diversity.