This massive steel pyramid can be entered by a set of jagged steps that let visitors stand in its heart.

This picturesque mansion has gone from opulent ruin to nature museum.

These locks on North America’s oldest canal are named after a porcine rock formation.

An icy lake tucked among jaw-dropping alpine panoramas.

Behold the rickety wooden glory of the world's oldest operating roller coaster.

This salt marsh in Southern France is as pink as the flamingos that inhabit it.

This futuristically sylvan church is a glass-enclosed marvel of modern architecture.

Devious political maneuvering and four ancient, working telescopes are central to the world's second-oldest observatory.

This erect, phallic geological spire wasn't always named so domestically.

An unassuming secret door once led to a legendary watering hole.

The centuries-old trees lining both sides of this dirt road may become Madagascar's first natural monument.

North America's oldest quarantine facility was built in response to Philadelphia's 1793 yellow fever outbreak.

This historic park site contains the last remnants of a once bustling canal system.

The sea once considered an ecological wasteland is now called "crown jewel of avian biodiversity" by scientists.

This Dresden church was purposely rebuilt Protestant after being demolished in World War II.

The last remnants of what was once one of the world's grandest hotels can now be found in a Manhattan subway station.

An apocalyptic seismic event creates a deadly chain reaction that ends with a 6-mile long lake developing within weeks.

This haunted corpse of a drive-in is now a graffiti-covered ruin.

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

This former football stadium seems almost abandoned but is still in use by the next generation of Scottish sports stars.

At the tallest peak in Colorado, an electrifying mix of thin air, lightning, and rivalry.

Modeled after a famous church in Vienna, Austria—but in Helena, Montana.

The highest point in Maine is a grand gift to the state citizens that also happens to be one end of the Appalachian Trail.

Enormous piles of historically significant stones, dumped by Congress in a forest, and abandoned for 60 years.