Hall of Infinite Doors

You approach the diamond door. It's not pure diamond, of course, but the lavish wealth involved in its creation is surely stunning. The door is made of some light, silvery metal, and has diamonds of all cuts, sizes and qualities embedded in its surface. Murky yellow industrial diamonds, rough and new, sit beside bright, cheery blue-white specimens. The handle is small, and you can barely grasp it, but it IS a pure diamond - one of the largest specimens you've ever seen, though barely bigger than a child's fist.

As you touch the door and prepare to enter, you feel an unpleasant nauseating feeling in the base of your skull. Your skin prickles, and something uncomfortably shifts into place in your mind. You can't tell how you came upon this knowledge, but you KNOW if you pass through this door, you won't be yourself anymore.