The private retreat of Booster Gold from where he can "protect time."
Said to be, "a citadel overlooking both time and space," and is, "outside the space-time continuum," the only entrance is through a large, glowing time portal.
From there, a passage leads to a large hall-like room with a transparent floor.
On one side is a desk with controls and with large displays in front of it from where Booster can monitor time-related matters.
Booster can be assisted there by his hovering, egg-shaped droid called Skeets.
- Vanishing Point (similar idea) at Wikipedia.