Gryben (officially known as Planet Gamma Beta Delta/97/5 Category Kappa Sigma 4) was a bubble world located at the Despond Irregularity. It was Gallifreyan territory.
The Time Lords used Gryben as a temporal enclave to which they diverted all unauthorised space-time vessels within the Time Vortex, allowing them to catalogue and interrogate them as to why they were in the vortex. According to Coordinator Narvin, a lot of the cases were aliens claiming to be political prisoners or that their planet was on the point of collapsing. The inhabitants grouped themselves according to which species they were. In the human outpost, a Free Time agent, Nepenthe, lived. (AUDIO: Weapon of Choice)
Robert Knox bought a TARDIS from a Nekkistani on Gryben. (AUDIO: Medicinal Purposes)