Dungeons: they have been a part of Minecraft since InfDev, but did not really take off in any form other than a mossy cobblestone brick for some time, when they expanded into desert temples, underwater temples, and others. As a sandbox game, Minecraft has never had much in the way of a narrative direction, instead having a world with a pre-defined (if vague) history - villagers, zombies, witches in swamps, and the like - and from there, the player creates their own lore, their own world. One nice thing about dungeons has always been the exploration angle, finding one deep in the wilderness and seeing what lies inside.
As part of the 1.9 update, Jeb mentioned that they were working on a new dungeon, with new blocks and mobs (the most recent one being the underwater temple, complete with new blocks and some really creepy fish), without embellishing on what may lie inside these new buildings. This brought an interesting question to mind: what do dungeons mean to you?
Dungeons seem to have very little lore attached to them (insofar as there is no in-game writings about them, or sentient guardians protecting them), but they nonetheless dot the landscape with enough frequency to merit some investigation. There are desert temples, the aforementioned sunken temples, subterranean strongholds with portals to the end: where do they come from? Who built them? No doubt this has been given some thought, and I'm curious what theories you have on them!
So, where do you think these structures come from? Who built them? Why are they here? Will we ever know, or is it a mystery doomed to float through time unanswered?