The impressive fortifications and defensive strategies used during Spain’s dramatic history of conflict, from the Middle Ages to the Civil War.

Discovering how France constructed ingenious fortifications, on a massive scale, to defend itself against attacks from the east.

The story of how the Netherlands, locked in a constant battle with water, has harnessed this threat to become a powerful European player.

The story of how Poland, one of the most invaded countries in Europe, has survived against all the odds.

How Britain has defended its coastline for nearly a thousand years since the Norman invasion – seeing off threats from Napoleon to Hitler.

Maritime archaeologist Andy Torbet investigates an ancient sea fortress that was crucial to Finland and military historian Alex Churchill investigates a stolen Soviet tank and the Molotov Cocktail.