The Gunung Mulu National Park may well be the single most impressive destination in all of Borneo. There are few parks in the world that pack so many natural marvels into such a small space. From some of the world's most incredible (and accessible) caves, to brilliant old-growth tropical rainforest and some out and out natural oddities such as the Pinnacles formation on Mt Api, Mulu National Park is truly one of the world's great wonders.