Ko Chang Island - Creek upstream from the waterfall (Thailand)
The hike up the creek above the waterfall is fantastic. Many small pools of water to bathe in. The Trail to reach the top of the waterfall is marked "No Entry" with a blue sign, because it is dangerous at the top of the waterfall. Be careful there.
It is the most remote part of the island, and you are unlikely to see anyone there. So be careful, don't go alone, as if you get injured you will probably die in this wilderness area.