Barbican — Middle Ages

The story behind the answer

It’s a detached, fortified outwork built in front of a castle or city gate to create a killing zone before the main entrance. Attackers were funneled into a narrow passage flanked by towers with arrow slits and murder holes, often secured by a drawbridge and multiple portcullises. Unlike a portcullis (just the grating) or a gatehouse (the main entrance building), this structure stands outside to shield the primary defenses; it’s not a courtyard like the outer bailey.

These outworks became common from the 13th century onward across Europe, seen at places like Carcassonne and Krak des Chevaliers. Their layered gates let defenders trap enemies between barriers, exhaust assaults, and buy time. The modern London district that bears the same name commemorates a long-lost example on the old city wall.