Visit the Great Siege Tunnels

About 300 tailless macaques live on the Upper Rock — Europe’s only wild monkeys, and famously light-fingered.

Explore the underground ossuaries in Paris, holding the remains of more than six million people

Sunken Byzantine reservoir under Istanbul, its columns rising from black water.

A chapel decorated with the bones of 40,000 people — chandelier included — beside the Gothic St Barbara’s Cathedral.

Visit Gibraltar, a British Overseas Territory located at the southern tip of the Iberian Peninsula, known for the Rock of Gibraltar and its strategic importance.

Ride to the summit of the Rock.

Dramatic show cave inside the Rock.

Southern tip facing across to Africa.