Zastros 8

Zastros 8 was a peaceful world and free-thinking paradise, with attractions such as sunshine, seas, beaches with ultraviolet light filtering, seaside resorts and computer sciences.

The Sixth Doctor tried to take Melanie Bush to Zastros 8, where a computer science conference was being held, but the TARDIS acted up due to the interference of the Nathemus and instead took them to Zastros 9, its counterpart. (AUDIO: The Brink of Death)