Landport Tunnel, Gibraltar
The Landport is a gate into the territory of Gibraltar. It was originally the only entrance to the fortification from the land and so was heavily fortified and guarded. There was also a moat covering the northern approach — the Landport Ditch. The ditch’s defences included a palisade and a gunpowder mine which could be exploded beneath an assault. To cross these defences, there was a drawbridge which was pulled up at night.