Secrets of the London Underground

TMDB score: 7.2/10

Railway historian Tim Dunn and Siddy Holloway from the London Transport Museum explore hidden areas of the London Underground that—despite being just feet away from where millions of people regularly travel—hardly anyone knows about. The pair will explore abandoned tunnels, secret bunkers and hidden staircases that have been concealed from public view for years.

Selected season 1, episode 1.