How Did History's Deadliest Sundial Work? | QI

You can now watch every series of QI, including this one, on iPlayer! ▶ http://qi.com/iplayer Follow QI on Twitter ▶   / qikipedia   Follow QI on TikTok ▶   / theqielves   Follow QI on Facebook ▶   / officialqi   Follow QI on Instagram ▶   / theqielves   Subscribe on YouTube ▶    / theqielves   For more visit ▶ http://qi.com This clip is from QI Series S, Episode 3, 'Shady & Shaky' with Sandi Toksvig, Alan Davies, Eshaan Akbar, John Barrowman and Victoria Coren Mitchell.