Helicon Prime

 was a luxury resort planet where people came to be pampered. It was one of the most exclusive places in the universe. It had Sympathetic Gravity, meaning water flowed upwards. It was the other side of the universe from Earth according to the Second Doctor. It used to be a retirement centre, but when fights broke out between the residents they moved the retirement centre to the Golden Section to calm them down. (AUDIO: Helicon Prime)