Alright, maybe they don't need a secret underground submarine lair, but the pirate bay that the Docm77 and ZipKrown people built in Minecraft has one. And, besides, the whole thing looks just too damn good.
The video is also showcasing the Japanese UGOcraft mod, that enables blocks to freely slide and rotate.
Can't think of anything missing from the lair, except maybe a giant volcano. The place already looks more like a giant fortress than a secret hideout. One has to think that they're not trying to stay on the down low. And with a build this great, they shouldn't!
The Pirate Bay - A Ugocraft Mod Showcase [YouTube]