The curios of pharmacist and collector Henry Wellcome.

The world's oldest optical museum is an odd collection where the exhibits look at you.

A charming 17th-century alley is lined with secondhand bookstores and antiquarian shops.

London's creepiest cemetery was once the site of dueling magicians and mobs of stake-carrying vampire hunters.

A huge musical instrument played by the ocean.

A stately palace has been converted into the world's largest cannabis museum.

A winding path built in secret on the edge of the continent.

A psychedelic labyrinth on the San Francisco bay.

Barcelona's historic 19th-century sewers, whose foundations were laid in medieval times, are open to the public for exploring.

One of Antoni Gaudí's most classic buildings is well-known for its "dragon-back" design.

Turntable anonymously received orphans, alms, and groceries.

Mountain where Jesus was first tempted by the Devil.

The studio of Catalonia's most famous theatrical designer remains exactly as he left it.

Unlike other abandoned asylums this empty institution welcomes visitors, just don't go in the buildings.

An extraordinary "City of Caves" carved from solid stone.

The remains of what was, not so long ago, the world's largest city.

A blooming house of worship for the masses.

Time has stopped at the house where Gandhi died.