Geryon's Eye
From Tardis Wiki, the free Doctor Who reference
Geryon's Eye was a time rift.
The ancestors of the Light Keepers were forced by the Lux to build a colossal Lumen on a nearby planetoid. Eventually, the Eleventh Doctor defeated the Lux by deflecting them into Geryon's Eye, transporting them through time and space.
Dorium Maldovar built the Maldovarium on the planetoid. Most of his customers arrived at the Maldovarium through Geryon's Eye, which also supplied him with some of his rarer and more expensive merchandise. (AUDIO: The Light Keepers)