Having survived the depths of Hell (described in the Inferno), Dante and Virgil ascend out of the undergloom, to the Mountain of Purgatory on the far side of the world. The mountain is an island, the only land in the Southern Hemisphere. Dante describes Hell as existing underneath Jerusalem, created by the impact of Satan's fall. Mount Purgatory, on exactly the opposite side of the world, was created by a displacement of rock, caused by the same event.[1] Dante announces his intention to describe Purgatory by invoking the mythical Muses, as he did in Canto II of the Inferno: