"Soviet forces have infiltrated a highly classified U.S. facility."
— Map description
Hangar 18 was released as part of the AnnihilationMap Pack for Call of Duty: Black Ops on June 28, 2011 for Xbox 360, and July 28, 2011 for PS3 and PC. It was originally a canceled map named Area 51. This is a medium sized map, set within Area 51. It has numerous easter eggs, such as alien corpses and a floating apple.
Hangar 18 also has many high elevated areas such as a cremation room, towers, and an SR-71 Blackbird.
Call of Duty Black Ops - Annihilation Multiplayer Trailer
Trivia
There is an apple levitating in what appears to be an electromagnetic field on the map. When shot, the bullets deflect and hit the walls around it.
The player can see three alien carcasses covered with blankets, which also have hands with four fingers and blue feet with four toes sticking out from the blankets.
It should be noted that these bodies have a tag on them which reads "Government Property."
In the alien room, there is an autopsy table that was thrown into a wall, and has large amounts of blood throughout the room, suggesting an alien escape.
There are numerous panels throughout the map that can be destroyed. If the action button is pressed, sounds will play. After being destroyed, these panels will re-spawn.
All the black vans' license plates say "exempt", and all the white vans' license plates say "U.S.Gov".