1960s television show

[macbeth]

Can anyone remember the episode of a show (that aired in the 1960s) where the Mona Lisa was shown in a labyrinth? I thought it might be 'The Avengers' -- there is an episode with the Mona Lisa "The Girl From Auntie" and there is an episode with a maze "The House That Jack Built" but I am sure there was an episode, perhaps from 'The Avengers' or maybe some other British TV series that fits the description I gave above. Perhaps some of the older members of this community could pitch in with suggestions. Thanks