- The Hollow Earth is an obsolete concept proposing that the planet Earth is entirely hollow or contains a substantial interior space. Notably suggested by Edmond Halley in the late 17th century, the notion was disproven, first tentatively by Pierre Bouguer in 1740, then definitively by Charles Hutton in his Schiehallion experiment around 1774.
- Doom (1993 video game) (Wikipedia)
Doom is a first-person shooter game developed and published by id Software. Released on December 10, 1993, for DOS, it is the first installment in the Doom franchise. The player assumes the role of a space marine, later unofficially referred to as Doomguy, fighting through hordes of undead humans and invading demons. The game begins on the moons of Mars and finishes in hell, with the player traversing each level to find its exit or defeat its final boss. It is an early example of 3D graphics in video games, and has enemies and objects as 2D images, a technique sometimes referred to as 2.5D graphics.