Rebuilt remains of a temple to Roman god Mithras.

Catacombs turned marketplace.

A 1,215-foot tunnel transports pedestrians beneath the River Thames.

The only university zoological museum in London houses extinct animals, bizarre natural history specimens, and a Micrarium of microscopic creatures.

One part local history, 99 parts gruesome haunted house.

This 1920s Dutch barge is now a floating bookstore.

Eighty million natural history specimens call this gargantuan museum home.

This museum is dedicated solely to this millennia-old handheld cooling device.

Stormy conditions send jets of seawater bursting through holes in the cliffs.

A historic Christian shrine nestled within a spectacular natural cave.

One of the largest ochre quarries in the world, hidden in a limestone landscape.

A landscape decorated with enormous skull sculptures.

Its interior is adorned with some of the best examples of early Christian mosaics.

An alchemist's “magic door” stands in the middle of a Roman park.

A freedman baker’s lavish tomb has a relief showing various stages of Roman bread making.

A spectacular walk on the flank of a gorge.

The London pub overlooks where the Mayflower was moored before setting sail for the New World.

This coffee shop lies hidden beneath a historic church.

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

A kaleidoscopic warehouse-maze of handmade neon signs.

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

This ornate Victorian marketplace was the setting for Diagon Alley and the Leaky Cauldron in the first ‘Harry Potter’ film.

The most famous location in China was home to whole dynasties worth of imperial rulers.

The world's longest outdoor covered escalator system transports commuters through Hong Kong's hilly terrain.