The story’s fairly well known: little girl writes into a newspaper to ask if there’s a Santa Claus–response from the paper becomes legendary. That’s where the line comes from: “Yes, Virginia, there is a Santa Claus.” This has been turned into everything from the title of an episode of Hercules to an excuse to rework Ultron against the Avengers.
Anyway, it was also turned into an animated television special in 1974. You might watch this and say, “Man, that looks a lot like Peanuts.” There’s a reason: it was animated by Bill Melendez.
The special was previously available on VHS and DVD but isn’t in print at the moment from what I can tell. So…enjoy.