Finsbury Park Reservoir. We set off early one morning after being passed access to this gigantic reservoir system that sits under Finsbury Park in the city of London. With the access point in a busy part of the city the cover of darkness was essential. We made our entrance and were instantly amazed at the size of this place. Built in 1903 by the Victorians, it has recently been closed off by Thames Water due to a crack in the roof, which for us was a chance to get inside to take a look. London currently holds a number of Victorian reservoirs and I can see myself returning soon for some more underground action. They simply just don’t build them like this anymore!