Battletowers adds towers full of chests and loot, but be carefull: They are guarded by monsters! When you get to the top there is a boss, which, when defeated, gives you access to the final chest at the top of the tower. After the boss is defeated, the tower starts breaking up making it more difficult to access the chests again.
The chests can hold anything from glass to diamond tools to aritfacts, but mob spawners guard the room. There are normaly two spawners in one room.
The boss sort of looks like a iron golem but stone and looks like it has one eye (painterly pack comes with the install).