Great Wall of China

The Great Wall of Cathay, or the Great Wall of China, lay along the course of the Yellow River. In 1289, Marco Polo's caravan travelled along the Great Wall for many miles. (TV: "The Wall of Lies") According to the First Doctor, it was twenty feet wide. (PROSE: Childhood Living)

History
The Tenth Doctor and Donna Noble visited the site of the Great Wall of China during the Qin dynasty, as it was still being built. (COMIC: The Immortal Emperor)

Before 2005, the Ninth Doctor visited the Great Wall of China and was photographed doing so. Clive Finch later showed this image to Rose Tyler. (PROSE: Rose)

In China, Harry's grandfather was once arrested, with his boyfriend, for attempting to steal a section of the Great Wall. (TV: Knock Knock)