Cyber-Tombs

Characteristics
The Tombs were small regtancular shaped rooms with pictures of Cybermen heads on the front wall. The Cyber-Control (Mondasian) tomb was a door with hinges instead of a plastic-like weak subtance like the other Cybermen tombs.

Usage
The use of the tombs were to hold "dead" Cybermen, who were actually hibernating. The tombs were really used when a great sickness killed of all the Cybermen. This sickness and a group of people and The Doctor, Jamie, and Victoria (DW: The Tomb of the Cybermen).

Cyberman are immune to diseases and viruses. The reason they locked themselves into tombs was because they were running out of power to revitalise themselves.