Tower of Gilgamesh

How it works:

There is a circle of red nether brick that marks out the area that you have to stand in to be selected to go to the Tower of Gilgamesh. The person that is closest to the center of that circle will be allowed to run the tower. Only one person can go every 3 hours, and PvP is enabled...

Once you kill the Gilgamesh boss, it has a chance of dropping a dungeon key, this chance is scaled to be less for higher difficulty dungeons, so less of those will drop.