World Championship Wrestling's Thundercage, based on the film Mad Max Beyond Thunderdome, is a large domed structure of steel bars engulfing the ring. Although it does not have a top, the sides curve in to prevent escape.
Mexico's AAA promotion tweaked the concept with the Domo de la Muerte ("Dome of Death"), which uses a similar cage but only allows victory by escaping through a hole at the top center. This variation is also used in Total Nonstop Action Wrestling, where it is called the Steel Asylum. In AAA it is typically used for multi-man "luchas de apuestas" (bet matches), with the last man standing in the cage losing his mask or hair.
The Thunderdome is a variation on the Thundercage, with the area near the top of the cage electrified. The only way for a wrestler to win the Thunderdome match is to have their opponents' "terminator" (usually a manager who stands outside of the ring) throw in the towel to stop the match. In another variation of this match, each pinned competitor in the match is handcuffed to the cage. The last man left is given a key to unlock his teammates to attack the other team, who are still handcuffed.
I only remember seeing this cage once in TNA, and it was the night Jeff Hardy made his return to TNA. I think everyone remembers the image of him sitting on top of that red dome cage. I can't really remember the match that was going on inside. But I keep wondering what ever happened to that red cage they had in TNA.