Kratie is on the Mekong, near some rapids. They turned them into a fun park, with many extremely long platforms built over the river, each with hundreds of hammocks and a few mobile kitchens. You lie in a hammock and watch the river rush past you.
It’s also one of the best places to see Irrawaddy freshwater dolphins, which are critically endangered. It’s been estimated that there are only 75 left in northern Cambodia. I was lucky to see a group of four, although they didn’t jump out of the water the way they do on the travel ads.