This national park dedicated to the tallgrass prairie ecosystem still displays its military past.

This World War II-era bunker is now packed with posters and props from movies and TV shows filmed nearby.

A historic and oft-filmed prison stands in a Chicago suburb.

What was once the second largest steel mill in the US is now a sprawling complex of modern ruins.

This historic Illinois "Muffler Man" has been converted from axe-touting lumberjack to rocket-wielding space ace.

An 18th-century estate owner thought these cottages were an eyesore, so he artfully disguised them as a church.

This massive Brazilian church is built like an angular, technicolor pyramid left by Mayans from the future.

Occupied for six centuries by Franciscan Order nuns, this monastery is an amazing ode to Catalán Gothic architecture.

The abandoned ruins of a beautiful medieval castle just outside Barcelona.

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

Seventy-five miles of limestone caves host more than a million bottles of wine beneath a sleepy Moldovan town.

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

This incredible collection contains rare steam-powered engines, rides, and trains.

This unassuming Victorian cemetery is the final resting place of author Lewis Carroll.

This quaint mortuary chapel hides a stunning Celtic Revival and Art Nouveau interior.

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

Once a prosperous mining village, this tiny Taiwanese town is now overrun with cute cats.

A science fiction-inspired apartment building designed by a famous Spanish architect.

A mysterious architectural gem in one of the most elegant areas of Buenos Aires.

One of the most easily accessible examples of the rare 1960s UFO houses.

A rare pod of derelict midcentury Futuro and Venturo houses lines a semi-abandoned beachfront resort outside Taipei.

This precariously perched fortress was once ruled by a crow-worshipping baron.

This picturesque castle in Poland has a rich history, including a legend that ties it to lost Incan treasures.

This street has over a half-dozen names, all at once.