Hong Kong
Hong Kong was a city on Earth.
History
In December 1974, the Sixth Doctor and Peri Brown saved a monk named Cheung from a Triad gang. (PROSE: Exclave)
In 1979, Tegan Jovanka went on holiday to Hong Kong. (PROSE: Cold Fusion)
Brigadier Lethbridge-Stewart met the Eighth Doctor in Hong Kong in 1988 where they encountered the Embodiment of Gris. (PROSE: The Dying Days)
Sarah Jane Smith assisted the Seventh Doctor in 1997 whilst investigating the Cortez Project in Hong Kong. (PROSE: Bullet Time)
In 2048, China was taken over by Hong Kong. (PROSE: St Anthony's Fire)
Behind the scenes
Complete film telerecordings of all four episodes of The Tomb of the Cybermen were found in Hong Kong TV station RTV/ATV and returned to the BBC in late 1991.