Portugal: Elvas – Forte da Graca

Forte da Graca is considered one of the absolute masterpieces of military architecture – perched high above the town of Elvas, this fortress was built to be utterly impregnable – and it succeeded, having never been successfully captured in battle. Built in 1763 in the king”s orders to protect the Spanish frontier and designed by German military architects – it is the largest bulwarked dry-ditch fortification system in the world. The fortress is multi-layer pentagonal star – each layer of walls and bastions, was meticulously calculated so that soldiers behind the parapets could fire upon attackers from multiple angles, completely eliminating any blind spots. There are three levels of forts within one, like a nesting doll. It’s a UNESCO World Heritage site.