4. Marco Polo - 7/7 Episodes Missing
Another pure historical and the first time that Doctor Who met a significant historical figure. This story takes place over about seven months and sees the TARDIS team travel with Marco Polo as he holds the TARDIS, intending to give it as a gift to a warlord in return for his freedom. Despite being such a long story, the soundtrack manages to entertain all the way through, never delivering a dull moment. This story uses a number of techniques not often used in Doctor Who, such as narration and visual maps, of course the map sequences no longer survive. This is another story that appears on most wanted lists quite often due to its ambition and impressive visual design. Unfortunately, due to it being completely missing from the archives, this is not something we can fully enjoy at the moment.