Ever wondered what the mouldiest Tube line is?
Well Daniel Henk from the University of Bath is here to help.
He collected fungal cells lurking on platforms at 12 stations across the Central, Bakerloo and Jubilee lines, and compared these levels with those in a London hospital and in one of the city's parks.
Apparently, people travelling on the newest line - Jubilee - breathe in more fungal cells than any other. That's twice as much as you would get in the park and four times as much as in the hospital.
But aside from mould levels, how much do you think you know about the Tube?
From ghost stations to plague pits and busking to Monopoly, take our quiz below to find out - and tweet your score to @indyvoices.