Discovery

Berlin Wall is a cancelled multiplayer map that was planned to be featured in Call of Duty: Black Ops.

Overview
Berlin Wall seems to be an snow-covered Russian base, not unlike Array.

Trivia

 * The map was apparently scrapped late in the game's development, as vote icons were created for it.
 * The flag of the U.S.S.R. can be seen on the grey dome in the loadscreen.