A popular 19th-century natural landmark is now hidden within a sprawling forest.

A chain of 16 wondrous lakes formed as a result of the gradual dissolution of soluble layers of bedrock.

The platform atop this verdant volcano was built with the help of a royal elephant.

Just your average Marie Antoinette–themed speakeasy in an abandoned 19th-century subway tunnel.

Turnip-shaped island just off the Michigan shore in Lake Huron.

A vast landscape of craters created by meteorites.

Stenciled handprints and wall paintings dating back 10,000 years, some of the earliest forms of cave art.

Remnants of the Nazis' occupation of Denmark linger along the sand.

This Catskills museum preserves stumps from the earliest known fossil forest on Earth.

Designed by Buckminster Fuller, this relic of the 67 Expo survived fire and ice.

This bronze sculpture on a former squash court marks the secret origins of the Atomic Age.

This historic-shipwreck-cum-diving-spot can still be seen poking its boiler out of the Lake Michigan waters that claimed it.

Fragments of architectural wonders from around the globe are embedded in the newspaper building's walls.

A speakeasy takes on Chicago's drinking culture.

A small part of lower Manhattan is actually made from a bit of England.

If drivers cross the rumble strip on this stretch of Route 66 at just the right speed it plays "America the Beautiful."

A strange rock in Chicago marks the spot where a tree once stood in honor of the 18th President.

One of the largest pieces of scientific equipment ever carried on a NASA space shuttle sits in a Chicago alley.

Years of archaeology, just chillin' by the water cooler.

This unauthorized stone mermaid was secretly carved out of public stone before being permanently preserved.

The site of the first couple's first kiss is commemorated by the most adorable presidential monument ever.

A Bibliophile's Dream.

Famously misunderstood wonder of the ancient world

The haunting "Hell House Altar" is one of the few remnants of an abandoned college that has been a magnet for local legends.