Shakespeare, David Bowie, Dr. Who, the Saxons, Druids and Romans are all claimed to have all made their mark on these massive man made tunnels.

This home on a quiet suburban street is completely covered with vibrant mosaics.

Fantastically decorated underground chambers built in the 1760s.

If God were a skater, this would clearly be His park of choice.

Human-made caves excavated to hide a secret society of wealthy pagans.

The hidden "ballroom" under a mansion lake was built by a criminal who ate a cyanide pill during his trial.

You'd never know the houses at 23-24 Leinster Gardens were fakes—until you see the train tracks on the other side.

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

A peculiar mansion built by the troubled heir to the Winchester Rifle Company fortune.

The abandoned "Red Star Train Graveyard" is the final rusting place for precious artifacts of train history.

This Budapest bar allows drinkers to leave their mark on the walls, floor, and even ceiling.

The London statue that imitates passersby.

The last four extravagant street signs of London's historic banking street.

This legendary stone is of unknown origin, and throughout history has been a literal touchstone for British leaders.

The last remaining example of the boatmen's perches that once dotted the south bank of the Thames.

The site of London's first coffee house has been serving refreshments of one kind or another for 360 years.

This ornate Victorian marketplace was the setting for Diagon Alley and the Leaky Cauldron in the Harry Potter films.

One of the world's largest collections of pathological specimens.

This wildly-tiled artist's palace is a living and growing account of the creator's life, loves, and labors.