In 1997, WWE introduced arguably one of the most popular stipulation matches in history, Hell in a Cell, to the delight of many fans.
The cell surrounded not just the ring but the ringside area as well, giving competitors room to really get each other going before slamming the opponent into the mesh wire.
The roof added another element of warfare and led to one of the most iconic moments in WWE history- Mick Foley being thrown off and then thrown through that very roof by the Undertaker, losing consciousness and some teeth along the way, narrowly escaping death only to return and wrestle a descent match. Yeah, that's right, both of those tosses happened at the BEGINNING of the match.
The Foley moment would attempt to be recreated several times, by himself in the 2000 No Way Out HIAC against HHH and by Rikishi in the 2000 Armageddon 6-man HIAC. Both of these spots were heavily staged and while they certainly were less risky, they were also less incredible.
The match has been used to settle many a feud, with some classics along the way- namely HHH v Jericho at 2002 Judgment Day, HHH v Michaels at 2004 Bad Blood, and Batista v 'Taker at 2008 Survivor Series.
The Cell has also had it's share of embarrassing moments- the two most notable being the rather uninspiring WMXV match (Undertaker v Bossman, with Bossman getting "hung" at the end) and the laughable Kennel in a Cell match at Unforgiven 1999 (Al Snow v Bossman) where barking (and crapping) Dobermans surrounded the inside ring (the return of the blue bars) and the competitors had to escape both that cage and the cell to win.