Khao Sok National Park

If your leg muscles have atrophied after too much beach-bumming, venture inland to the wondrous 738-sq-km Khao Sok National Park, halfway between the Andaman and Gulf coasts. Many believe this lowland jungle (Thailand's rainiest spot) is over 160 million years old, one of the world's oldest rainforests. Dramatic limestone formations and waterfalls cascade through juicy thickets drenched with rain and morning dew. A network of dirt trails snakes through, allowing visitors to spy on an exciting array of indigenous creatures.

Khao Sok’s vast terrain makes it one of the last viable habitats for large mammals. During rainy months you may spot bears, boars, gaurs, tapirs, gibbons, deer, marbled cats, wild elephants and perhaps even a tiger. And you'll find more than 300 bird species, 38 bat varieties and one of the world’s largest (and smelliest) flowers, the increasingly rare Rafflesia kerrii, which, in Thailand, lives only in Khao Sok. These giant flowers can reach 80cm in diameter.

The best time to visit is the December-to-April dry season. During the June-to-October monsoon, trails get slippery, flash flooding is common and leeches come out in force, though European summer holidays keep the park busy. Animals leave their hidden reservoirs throughout the wet months, so you’re more likely to stumble across big fauna.