The Burning Hells, or simply, Hell is the residence of the Demons and Great Evils - Diablo, Baal, and Mephisto. It is from here they launch their attacks on the mortal and heavenly plains.
In Diablo II the player enters The Burning Hells to slay Diablo. The zone is similar to that described in Greek mythology, with the paths being made of black stone surrounded by lava and filled with horrible monsters and forgotten sinful souls trapped in their fate. Living up to its name, it is a nightmare. You travel into Hell via the Pandemonium Fortress. Hell in Diablo II is the location of the Outer Steppes, Plains of Despair, City of the Damned, River of Flame, Hellforge and the Chaos Sanctuary.
In Diablo I, your character travels into Hell to slay the Demon Diablo. Unlike the Hell of Diablo II, this hell is dark, and full of bodies bon and blood, which its most dominant feature.