Lop

Lop was a town in 13th century Cathay, located on the edge of the Gobi Desert. A way-station was located there run by Yeng.

The First Doctor, Susan, Ian, and Barbara stayed in Yeng's way-station in Lop for a few days, while travelling with Marco Polo from the Plain of Pamir to Shang-Tu. (TV: Marco Polo)