The Great Siege Tunnels

During the Great Siege of 1779-83, Gibraltar's defenders answered an engineering riddle - how to mount guns on an unclimbable north face - by digging: soldiers carved galleries through the limestone by hand and gunpowder, opening embrasures that still stare over the isthmus and bay from inside the Rock itself. The tunnels' cool passages walk visitors past cannon at their ports, tableaux of the digging teams, and windows in the cliff face with the views that justified the labour. The system's later extensions honeycombed the Rock further, making 'solid as the Rock' geologically ironic ever since.

What you actually see

• The hand-carved galleries - 18th-century digging at cannon scale.
• The embrasure windows - gunports in the sheer north face.
• The cannon stations - guns at their original ports.
• The bay panoramas - the views the labour purchased.

When to go

Year round - the tunnels keep their cool; pair with the upper reserve's macaques and viewpoints in one Rock day. Mornings beat the tour-group waves.

Honest expectations

Passages involve slopes and steps in numbers - comfortable shoes and moderate fitness suffice; claustrophobia rarely troubles the generous galleries. The combined-ticket structure rewards planning the whole Upper Rock day.

Nearby

The macaques' dens, St Michael's Cave and the cable-car summit.