I recently had this idea while reading the abandoned underground mines suggestion. I thought it might be cool.
The Idea:
Imagine your exploring the world... And in the distance, you see a large structure. But wait, you didn't build that... And it seems to be made out of Mossy Cobblestone! You go to investigate, and find that it is in ruins. You enter the structure. It seems safe enough. But suddenly, you step on an unseen pressure plate, and almost immeadiatly you are hit by a hail of arrows from unseen dispensers in the walls. You manage to survive, and venture deeper inside the structure, only to find that it is infested by mobs of all kinds. You fight your way through them, and eventually reach an area with several rooms. A few of them have chests inside... Along with multiple mob spawners. You manage to defeat the mobs, and open the chests and take your rewards.
Basically, they are like above-ground, massive dungeons. You would find them very, very, very rarely(They are about as rare as diamond), and they would be filled with traps such as dispensers, as well as mobs. Most of the structure would be mossy cobblestone, and there would be the occasional pile of dirt, or sand(if your in a desert biome). Stairways would be broken, walls and ceilings would be crumbling, etc.
The Idea:
Imagine your exploring the world... And in the distance, you see a large structure. But wait, you didn't build that... And it seems to be made out of Mossy Cobblestone! You go to investigate, and find that it is in ruins. You enter the structure. It seems safe enough. But suddenly, you step on an unseen pressure plate, and almost immeadiatly you are hit by a hail of arrows from unseen dispensers in the walls. You manage to survive, and venture deeper inside the structure, only to find that it is infested by mobs of all kinds. You fight your way through them, and eventually reach an area with several rooms. A few of them have chests inside... Along with multiple mob spawners. You manage to defeat the mobs, and open the chests and take your rewards.
Basically, they are like above-ground, massive dungeons. You would find them very, very, very rarely(They are about as rare as diamond), and they would be filled with traps such as dispensers, as well as mobs. Most of the structure would be mossy cobblestone, and there would be the occasional pile of dirt, or sand(if your in a desert biome). Stairways would be broken, walls and ceilings would be crumbling, etc.
So what do you think?