Lop
From Tardis Wiki, the free Doctor Who reference
Lop was a town in 13th century Cathay, located on the edge of the Gobi Desert. (TV: Marco Polo) While Marco Polo described it as a town, it was not much more than an oasis surrounded by tents and wooden shacks. The main building was a way-station, run by Yeng. (PROSE: Marco Polo)
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)
