This is a great 40 minute film about the Tube at 100. Made in 1963 it provides a brief history of the Underground network up to that point. It's interesting to see that while many things have changed in the last 50 years, many haven't. For example, the Tube in 1963 looks about as crowded as it is today. Moreover, they were still trying to explain to people to stand right and not crowd the doors. If people haven't learned these lessons in the past 50, I don't think there's a lot of hope in the next.
Some highlights include footage of the yet to be opened Victoria line (next up in my Tube Challenge) being built and the building of what become known as Millbank Tower (originally named Vickers Tower), the Shard of it's day. There is even mention of driverless trains, something that's still being talked about 50 years on.
If you have 40 minutes I highly recommend giving it a watch, a great slice of history.