Whether it's London's rich history or London's subterranean secrets that gets you excited, you're likely to jump at this rare chance to explore Clapham South's deep-level shelter. Just one of eight such shelters that exist across London, the underground marvel contains over a mile of passageways and has been used as a shelter during the Blitz, temporary accommodation for Windrush migrants and even a budget hotel over the years.
Want to take a peek around for yourself? London Transport Museum's Hidden London series is offering tours this August and September. You'll have to be quick though, spaces will sell fast.