Drawbridge

A drawbridge is a bridge that can be moved in order to stop or allow passage across it. They were often built as part of medieval castles which had moats.

Drawbridge at the fort of Ponta da Bandeira; Lagos, Portugal

Modern drawbridges are often built across large, busy waterways. They can be lifted to allow large ships to pass or lowered to allow land vehicles or pedestrians to cross.

Animation of a rolling lift bridge (such as the Pegasus Bridge)