Die Maschine is the first map introduced in Black Ops Cold War Zombies. Die Maschine is a big map containing a reiterated version of the classic Nacht Der Untoten (the first-ever Zombies' map) placed right at spawn. At surface level, it might seem as if there's not much to do. However, the map holds a secret underground facility that belonged to the Nazis, where particle-colliding experiments were carried out under a project named "Projekt Endstation."
Die Maschine has two levels - surface level and underground facility. You can find the power button (just like with any other zombie maps) in the underground facility. Some areas of the map on the surface level can only be accessed once you've turned on the power.
The surface level has one central building, which is the revised version of Nacht Der Untoten. It has a yard to the east of Nacht, which is your spawn point. You will find a pond area to the west, and to the north, you will find a crash site. Both the crash site and the pond area have a tunnel that joins and leads to the underground facility entrance.
Upon entering the underground, you will find a lot of rooms in the facility. The underground facility houses Medical Bay, Main Power Room, Control Room, Weapons Lab, and a Particle Accelerator Room. The power is turned on from the Main Power Room, of course.
You can use the Dark Aether portals to visit the corrupted side of the same locations as part of the main easter egg or just for your own amusement.
You can find more information about Die Maschine on our dedicated Zombies guide here.