A short flight across the South China Sea from Kuala Lumpur lies Borneo, famed for its untamed landscapes that range from tropical rainforest to rugged mountain, diverse wildlife and spectacular dive sites. The northern part of the island (known as Kalimantan in Indonesia, to which the largest part belongs) consists of two Malaysian states, Sabah and Sarawak, plus the tiny independent Sultanate of Brunei. From Sarawak's capital, Kuching, you can head out to nearby Bako National Park for a taste of the jungle. One must-see is Gunung Mulu National Park, where one of the world's longest networks of limestone caves is set amidst dense rainforest. One cave is so massive that St. Pauls' Cathedral could fit inside its mouth, and each day at nightfall two million bats make a dramatic exodus in search of food. Other caves contain spectacular stalactite and stalagmite formations, or unique species of orchid and pitcher plants. If, however, you prefer to stay above ground, you can test your stamina by trekking to The Pinnacles, the serrated limestone peaks that dominate the high country.