Monty Python fans will recognize this abandoned mine as the Cave of the Killer Rabbit of Caerbannog.

This sublime architectural marvel is a rare example of an expressionist church.

Nestled amid the peaks and lochs of the Scottish Highlands, this inn and pub has played host to outlaws and ghosts.

This legendary dessert was served to Nobel laureates for decades.

Bored potato-guarding Nazis etched their thoughts onto a brick storage building in Copenhagen's Meatpacking District.

A 19th-century subterranean reservoir repurposed as a contemporary art cave.

Pre-Nazi swastikas adorn the sculpted pachyderms flanking this brewhouse portal.

Modern commuters still pass through this 2,000-year-old Roman archway.

This structure among the trees was the result of divine inspiration.

Henry VIII's forgotten castle was built by the gunpowder-obsessed king to be defended solely by cannons.

Grotto replete with mystical designs laid out in glued shell mosaics.

This skewed English house has looked like it's going to fall over for centuries.

A Neolithic burial site built 1,000 years before Stonehenge.

A once-magnificent collegiate church is falling into ruin.

Sculpture designed by Turkish artist and professor Mehmet Ali Uysal.

A magical and peaceful ruined Cistercian abbey in what is now southern Belgium.

Ancient man-made caves underneath small town Belgium.

A Belgian self-built tower inspired by the Bible and ancient civilizations.

Pagan monument converted to Christianity with the population.

An ancient and majestic fortress that played an integral role in Portugal's road to independence.

This eccentrically decorated palace is replete with grottoes, fountains, tunnels, and caves.

This unreal Portuguese palace looks as though it's made from a pile of different castles.

This Industrial Age architectural and engineering gem helps visitors and residents alike traverse Lisbon, “The City of Seven Hills.”

Legacy of the earthquake that nearly wiped Lisbon off the face of the Earth.