These bleak 800-year-old ruins were once the royal residence of choice for hunting in Sherwood Forest.

This 600-year-old tower was built as a comfy residence for cherished pigeons.

This Victorian marvel of engineering and artistic prowess is nicknamed the "Cathedral of Steam."

When it came to designing his own small office building, the eccentric architect wasn't afraid to show the world what he could do.

At 1,732 feet above sea level, this spectacularly isolated yet surprisingly bustling bar is the highest pub in Britain.

England's largest white horse isn't even white.

Although it appears ancient and mysterious, the quirky folly was actually built 200 years ago by an eccentric estate owner.

Astonishing rock formations dot the Brimham Moor landscape.

The ghosts of Britain's telecommunication past sit rusting away in a small village in England.

This former quarry is now a vibrant labyrinth of magical in situ sculptures.

This silent sentry in the crypt below a large Gothic cathedral is often knee-deep in water.

The biologist's fossilized headstone was meant to reflect his love of nature. Its, ahem, unusual shape is probably just a coincidence.

For a century, the tallest building in Tasmania was a tower built to manufacture ammunition.

This historic Australian bridge was built by convicts with giant stone spikes to prevent cattle from falling off the sides.

After much poking and prodding, this island is decidedly not a magnetic anomaly, but it sure is pretty.

This extraordinary geological oddity resembles human-made pavement.

Once housing children next to hardened criminals this historic jail once displayed Ned Kelly's skull until it was stolen.

This historic Melbourne bullet factory is fully encased in a massive glass and steel cone.

The word 'wunderkammer' translates as 'wonder-chamber'. This Wunderkammer is both a museum and a retail store.

The platform atop this verdant volcano was built with the help of a royal elephant.

A solitary tree has grown up all alone on Lake Wānaka, backdropped by the beautiful Southern Alps.

New Zealand's epic shrine to all things puzzling.

A perfect turquoise lake colored with glacier dust.

This strange geological landscape erupts with sudden bursts of water.