Normally, deep dark biomes try to avoid spawning beneath water, but since deep lakes don't have their own biome, we get this. An ancient city not only exposed, but also partially flooded, meaning that all you need is a door to get some end-game loot. Also, the lake itself is pretty scenic, which is nice.
Seed: 2153322630318242886 at 4150, -2200
by EthanTheInteresaunte