According to Hebrew legends, the Chamber of Gaf (also referred to as the Hall of Souls), is where souls gather before they are born as humans. If it ever becomes empty, a soulless child will be born, which is considered to be the omen preceding the destruction of the world.
In Neon Genesis Evangelion, the following announcement can be heard during experiments at the South Pole: 'Retrieve thermal dampening system as soon as the door to the Chamber of Gaf opens.' The announcement was followed by the awakening of Adam and occurrence of the Second Impact.
Based on Neon Genesis Evangelion Platinum: 04 DVD Booklet