The Bunker was supposedly an old abandoned Soviet Rail Bunker that was found by Duncan. He brought Lewis there so they could start making missiles to combat Sips and Sjin. After fixing up some of the Bunker they found an iron golem that they named Comrade, as well as some chests guarded by him. They then decide to test out some of the bombs in the chests but ended up killing each other and covering the Bunker in debris.
The Bunker was slightly damaged in Voltz Episode 24 when Ridgedog launched an Ender Missile at the roof which sucked in multiple blocks as well as Duncan prior to multiple endermen invading the base. Simon and Lewis killed them at the cost of all their equipment by pouring lava into the control room. The three of them then attacked Ridgedog's base in revenge.
Later in the episode they fixed some minor damage and built a new Missile Launch bay. Unfortunately the Bunker was never completely restored. The current damage to the Bunker is a blown-out roof.
The Bunker is made up of two rooms with a hallway running through it. One room houses the machines and stairs to the roof, the other one houses a chest and the entrance to the basement. The roof houses a missile launcher and a (broken) anti-ballistics system. The basement consists of a storage room and a nuclear fission reactor. In the reactor room there are stairs leading down to a mine. A hole in the stairs leads down to a sub-basement containing a nuclear fusion reactor and a particle accelerator.