The setting of the vast majority of Undertale, the Underground is a large region underneath the Surface of the Earth, which houses the kingdom of Monsters. Exit from the Underground is blocked by the Barrier which was placed by the Humans ages ago. It is accessed by humans, the player included, by way of a hole in Mount Ebott. It is ruled by Lord Asgore, and formerly by his ex-wife as well, Toriel. Spanning several different climates, the Underground features the cold and wintery Snowdin, the wet and cavernous Waterfall, the blistery and barren Hotland, the technologically advanced Core, as well as the Capital.