Shan Shen was a planet inhabited by humans or a humanoid species with a Chinese culture. Some streets here were filled with flags, pagodas and various crowded stalls.
The Tenth Doctor once took Donna Noble to Shan Shen. She had her fortune read by a fortune teller working with the Trickster's Brigade.
After the Trickster's attempt to change history backfired, all of the writing on the planet - including that on the Doctor's TARDIS - changed into the phrase 'Bad Wolf'. This, coupled with the ominous tolling of the Cloister Bell, warned the Doctor that the end of the universe was approaching. (TV: Turn Left)
It is likely that Shan Shen was a planet reserved for the Chinese, possibly during the Second Great and Bountiful Human Empire, when the majority of humanity left Earth to live on other planets.
Also, Donna told the fortune teller about Earth as if she hadn't heard of it. It could be that Shan Shen was so far from Earth that Donna assumed she hadn't heard of it.
