There's an incredible underwater restaurant in Kristiansand in southern Norway. Designed by award-winning architects Snøhetta, Under looks like a rock formation rising from the sea.
The San Luis Obispo County stretch of the Californian coast is home to a world of arches, caves, grottos and rock gardens that are only accessible from the water.
A cliff face in Maharashtra hides remarkably well-preserved murals, carvings and sculptures dating from the 1st or 2nd century to the 5th century.
Originally a fortress and then a royal residence, today the Louvre holds one of the world’s finest collections of art and architect I.M. Pei’s glass pyramid has become an iconic Paris landmark.
There's plenty to explore beneath the surface of the world-famous Colosseum in Rome. Go underground to visit the dungeons where gladiators and animals waited before their fight.
This UNESCO salt mine in Poland has been mined since the 13th century. It's nine levels deep but only sections of the first three are open to the public
Above ground, Antwerp is a fascinating mix of medieval history and contemporary cool. This unusual tour beneath its streets explores the network of sewers.
Adventurers will love the four-hour Deep Darkness tour inside the lower caves at Indiana Caverns. It's physically challenging.
Port is at the heart of Porto. Portugal’s second city is the place where the fortified wine is aged in tanks or wooden barrels and then exported.