The inside of a recently discovered silo, apparently quite warm in temperature.

A Silo is an ancient tech left over from the old world before the Great Whump. It contains a number of power conduits linked to a grid, and was a source power generator to the people who came before the current inhabitants of the Ava.

The full power cell of each silo is an unknown structure or material deep beneath the Avantsphere, yet to be discovered.

A noteable example is the first reactivated silo on record, Silo LX-59 and its first Si-Mas named Cheversly.