Era: 2300 A.D.
Music: Chrono Trigger, Sealed Door
The Keeper's Dome is a facility in 2300 A.D. built by Belthasar to house the Epoch and finish his other projects. The solitude of the future caused the guru to become unstable, and he transferred his memories to a Nu. This being maintained the Epoch's hangar until it was no longer required, and then was shut off to sleep beyond the flow of time.
Translation: Watcher's Dome
Watcher as in one who keeps watch over something, like a guard or sentry.