Exploring the ways different countries protected their borders over the past 1,000 years.
Nautical archaeologist Andy Torbet explores an old sea fort, crucial to Finland's defence, while historian Mika Kulju discovers how the Red Army was defeated in 1940. 7+. (3 of 6)
Archaeologist Tony Pollard explores Rochester Castle and an infamous medieval siege, while military historian Alex Churchill discovers how Britain tackled Napoleon. 7+. (1 of 6)
Tony Pollard visits the holy site of Jasna Gora to reveal how a monastery survived a brutal siege, while Alina Nowobilska explores the epic Modlin Fortress. 7+. (4 of 6)
Professor Danielle George explores star fortress Bourtange to discover how it held out against two brutal sieges in the fight for Dutch independence. 16+. (5 of 6)
Professor Tony Pollard studies the genius of French fortress construction under Louis XIV, while Arthur Williams discovers why the Maginot Line failed as protection. 12+. (2 of 6)
Historian Onyeka Nubia investigates the Moorish forts, while Spanish Historian Claudio Lozano reveals how Cádiz resisted attacks from Queen Elizabeth I. 16+. (6 of 6)