Blizzard released a screenshot of what is at the bottom of the hole, in an image entitled ''Wizard and Templar Meet a StrangeStranger'', which can be seen below. It is hidden behind a link to prevent spoilers:

A meteoroid is a sand- to boulder-sized particle of debris in the Solar System. [http://en.wikipedia.org/wiki/Meteor] The visible path of a meteoroid that enters Earth's (or another body's) atmosphere is called a ''meteor'', or colloquially a ''shooting star'' or ''falling star''. The term "meteorite" refers to the source of light, while the term "meteor" refers to what is generally seen in the sky by the human eye. If a meteor reaches the ground and survives impact, then it is called a ''meteoroid'' [http://www.mentalfloss.com/difference/meteor-vs-meteorite-vs-meteoroid/] or, depending upon circumstance and elemental composition, a ''chondrite''[http://meteorites.wustl.edu/id/ordinary_chondrites.htm]. Many meteors appearing seconds or minutes apart are called a ''meteor shower''. The root word meteor comes from the Greek meteōros, meaning "high in the air". Furthermore, the color of the meteroid's trail when it is entering the atmosphere is determined by the atomic composition of gasses surrounding the rock. Different atoms will burn at a different color in the light spectrum, but meteoroids often burn white due to a varied composition.