The remains of a failed attempt at medieval nerdery are hidden deep in the woods of Virginia.

Once described as the "Eagle's Nest," this ruined ancient city rests on a remote mountaintop.

Running under an entire mountain, the longest highway tunnel in North America is kept fresh using portal fans and jet fans.

This small city where almost everyone lives in the same building can only be reached via North America's longest tunnel.

This Italian foot path winds through the mountains via 52 individual tunnels.

This Nazi-built amphitheater was constructed on a sacred mountain site used by various German cults.

The highest point in Washington state is a volcano covered in glaciers.

When Croatia became independent of Yugoslavia, the splintering governments left behind these concrete tunnels.

Formerly Yugoslavia's "forbidden island," this sleepy little city still holds the abandoned remains of military strongholds.

The highest peak in Utah is the hardest to reach, but only if explorers choose the hard way.

These powerful, if squat, Canadian waterfalls flow in different directions depending on the time of day.

This series of underground chambers contains Europe's largest subterranean lake that is slowly drained each day.

These bronze pamphlets remember a remarkable group of Germans who fearlessly opposed the Nazis in the very center of their power.

This wooden hotel is a temple to German sustainability and forest conservation.

This collection of over 50 murals celebrates Brussels' rich history as the self-proclaimed home of the "comic strip."

This massive stone and steel monument remembers a century-old battle that cost thousands of lives and nearly destroyed the city.

This Canadian island is a veritable garden of decay with countless abandoned structures dotting the landscape.

Hamburg's first legal sex work is relegated to a gated street that still does not allow pedestrian women.

The site of one of Japan's very few American occupations during World War II still holds the relics of a roundly disastrous campaign.

Located in the house where Gustave Flaubert was born, this odd museum has more to do with medical grotesquery than the Western novel.

This former limestone quarry is now a subterranean wonderland of grand stonework.

The small town of Poulsbo in Washington state is the next best thing to the Kingdom of Norway.

The Icelandic Sea Monster Museum explores the area's history of aquatic cryptid sightings.

The world's only official college program focused on "clown therapy."