A copy of this episode was discovered in 2013, restored and released to iTunes late in 2013. A DVD is due to be released in the UK in February 2014.
The Web of Fear is Brigadier (still a colonel here) Lethbridge-Stewart's first appearance in Doctor Who. His first episode was technically The Web of Fear, Part 3, but that episode is one of those that was wiped by the BBC and no known copy of it exists.
This episode takes place in the London Underground in 1975.
This episode was watched by 8.4 million viewers on its original transmission.