A fairytale Gothic castle steeped in Nazi treasure conspiracy theories.

This desert oddity hides in plain sight thanks to a cartographic error and a desert explorer with a punny sense of humor.

Deep vertical fissures like miniature slot canyons cut across the cemented volcanic rock of Black Point above Mono Lake.

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

An abandoned railroad tunnel is now filled with bioluminescent bugs.

This seaside Italian village doesn't just look Escher-esque, it actually inspired the mind-bending artist.

This tablet indicates where the tragic monarch returned to begin her tumultuous downfall.

Rebuilt several decades ago, its striking murals prevent it from being reconsecrated as a church.

An architect transformed this abandoned cement factory into his castle-like workshop.

This eclectic, mosaic-clad home includes a bamboo ping-pong loft and a "Whispermaphones" intercom.

A glimpse into the festive and private lives of medieval Europe.

An eerie, decaying ghost town destined to fade into the forest.

The first steel dam in the world and the only one still functional in the United States.

A once-fairy tale mansion now stands in a state of disrepair.

A modern English garden of eccentric beasts, follies, and oddities.

This museum devoted to the gothic author holds such interesting ephemera as his socks and walking stick.

This gorgeous reading room houses the oldest and largest art history library in the Netherlands.

The sculpture is made of more than 100,000 knives collected to raise awareness about violence.

This whimsical park encourages its visitors and wildlife to roam on and around the various works of art.

Large-scale contemporary artworks tower over fields and lurk in forests around a Jacobean manor house.

An Aztec snake god has taken the material form of an apartment complex.

This once-popular otherworldly landscape was formed by one of the largest volcanic eruptions in history.

An enchanting work of outsider art, full of whimsical sculptures and carvings.

A Welsh sheep farm provides daily (non-sheep) meals to red kites, producing dazzling displays of aerial acrobatics.