Unthinkable City
From Tardis Wiki, the free Doctor Who reference
The Unthinkable City was the location of the auction of the Relic. Qixotl used block transfer computation and matter augmenters to create it on Earth in an East Indies rainforest in 2069. The city had a Brigadoon circuit which kept it out of temporal phase with its surroundings, allowing entry only to those that Mr Qixotl had invited to the auction.
Krotons once took over a Dalek ship in order to attend Qixotl's auction in the Daleks' place. It landed on the top of the Unthinkable City and was explored by the Eighth Doctor.
Kamala sold t-shirts in his shop in the area that said "I SAW THE UNTHINKABLE CITY AND LIVED!" (PROSE: Alien Bodies)
