T'ien Shan as shown in the cover of The Rise of Endymion
T'ien Shan (translated from Chinese as the "Mountains of Heaven") is a world located within the WorldWeb of the Hegemony of Man. It is the stage for many of the events that take place in the last novel of the saga, The Rise of Endymion.
T'ien Shan's most notable geoplanetary features are its planet-spanning mountain ranges; the higher reaches of these mountains are the only habitable regions on the planet, as the lowlands are covered in seas of acid and clouds of phosgene gas.