Mister Rogers' Neighborhood (1968)

Season 24: Episode 9

Rogers uses a long piece of plumbing pipe to simulate a tunnel in which blocks and a car could travel through. Mr. McFeely shows a video of passing through a car wash. In the Neighborhood of Make-Believe, King Friday hears of the search for the lost tunnel. Lady Aberlin finds all the pieces to the old parable about it, and it is very close to X's tree.