The Fabulous Baron Munchausen is a 1961 film by Czech director Karel Zeman. It mixes live action with animation, and it's interesting to see that combination.
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Spinning Image concludes, "It's lovely to look at, and one of the director's most rightly lauded works." FilmReference.com calls it "a tour de force exercise in how film form can properly illustrate the conceit of its subject." MSN has an overview. There is no critics score at Rotten Tomatoes, but the audience rating is 86%.