Urgrund

History
Urgrund was the world inhabited by the Old Gods before it was split in two. The planet was ruled by the god-king Yuga Khan, who amassed an army to attack Earth, in search of the Anti-Life Equation.

Following Mobius' destruction of the White Lantern, a shockwave was sent through time and space, splitting Urgrund in two, eventually creating the twin worlds of New Genesis and Apokolips.