Khao Sok National Park

The rainforest here is older than the Amazon, and you feel it. Limestone karsts rear up out of the trees, the canopy is thick enough to swallow noise, and the whole thing sits in southern Thailand between Phuket and Surat Thani, which makes it the one inland trip worth breaking up a beach vacation for.

Cheow Lan Lake is the reason most people come. It's a green reservoir studded with floating raft-house bungalows, and the routine is simple. Longtail out in the mist, listen to gibbons at dawn, swim off your porch. Back on land there are jungle treks to waterfalls, river tubing, and enough hornbills and langurs to keep the binoculars busy. Wild elephants exist. You probably won't see one, so don't build the trip around it.

My advice is two nights on the lake rather than one. A day trip from the coast means three hours of driving each way and you'll spend the good hours of light in a van instead of on the water.