Marco Polo is a serial in the British science fiction television series Doctor Who, which was first broadcast in 7 weekly parts from February 22 to April 4, 1964. Although audio tracks and still photographs of the story exist, none of the footage of this serial has survived. This is the first "pure historical" Doctor Who story, in that there are no science fictional elements other than the fact that the Doctor and his companions have travelled to the past. I watched the Loose Cannon reconstruction of this story and it's a great loss that the original footage has been lost. It's clear from the still pictures used by Loose Cannon that the sets and costumes were very well done, and that this story must have been a great spectacle.
The story involves the TARDIS landing in Tibet in the late 1200's. The Doctor and companions meet Marco Polo while he is traveling along the fabled Silk Road to see the Emperor Kublai Khan. Marco Polo steals the TARDIS and a long journey ensues with the Doctor, and companions, traveling with Marco Polo through several adventures, misadventures, etc, until they reach Peking and the court of the Khan.
It's a very interesting and likable story. I really wish the video were available rather than it being reconstructed from telesnaps.