Desert Temples, also called Pyramids or Desert Pyramids, are generated structures that spawn in Desert Biomes. There are always four chests below the ankh symbol on the floor, as well as a pressure plate directly below the blue wool block. When stepped on, the pressure plate will detonate nine TNT blocks below the floor, resulting in death for all players in the room and for the chests to explode as well. Desert Temples sometimes spawn in place of Jungle Temples in Jungle Biomes, but this is extremely rare. Desert Temples are a bit more common than their jungle counterpart. Sometimes, the Temples will spawn completely covered in sand, making them very hard to find. This is also quite a rare occurence. 

As of 1.8, Desert Temples have Stained Clay instead of wool on their floors. This makes Desert Biomes the second biomes with Stained Clay, Mesa Biomes being the first.