There can be few more relaxing ways to explore the watery hinterland of Cambodia and southern Vietnam than by taking a leisurely river cruise through the verdant delta of the mighty Mekong River, the most biodiverse river in the world.

With more than a thousand limestone peaks rising out of its crystalline, emerald waters, Halong Bay is is rightly viewed as one of the natural wonders of Vietnam, and is one of the country's five UNESCO World Heritage sites. Lesser known, and therefore less touristed are the equally stunning Lan Ha and Bai Tu Long Bays.

The Sepik River is one of two vast tropical river systems in Papua New Guinea that meander through the densely forested lowlands of the world's second largest - and the world's tallest - island. Along the banks of the river and its many tributaries live sparsely scattered, remote villages scarcely contacted by the outside world, where people live a lifestyle that has changed little for thousands of years.

Cambodia has some spectacular opportunities for the more adventurous, active visitor. The mountainous northeast provinces of Ratanakiri and Mondulkiri are still largely forested and home to a number of tribal minority peoples, while the Cardamom Mountains of the southeast are considered to host the largest remaining contiguous block of rainforest on mainland South East Asia.