Where I was yesterday - it's worth going

I was assigned which entailed gathering a large number of skulls. And I approached a certain person....Consequently, I found myself travelling on a speed boat, jetting across a river/sea/lake? passing some very tiny islands with greenery and small wooden huts. also saw children playing happily on these islands. What a breath-taking scene! The boat mounted a slope, flew and came to a stop at one of the islands, we entered the hut.......Where is this place???