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

Where three rails and three centuries of transportation meet.

This shale formation along the Appalachian Trail once inspired the third president of the United States.

The last holdout of a pre-Civil War rebel who took the matter of slavery into his own hands.

Time travel with sweets across history at this research-based candy store.

Look closely and you’ll notice that the color changes a third of the way up the tower.

A charming tour of the umbrella, tin-can, and drinking-straw capital of the world.

This earthwork installation sits on a grassy hill, celebrating Iceland's past and present.

This colorful gate stands as an entrance to the walled city of Old San Juan.

Legend tells how a Spanish soldier disappeared from this isolated sentry box without a trace.

This tiny home was originally a narrow alleyway.

This bleach-white graveyard overlooking the ocean is accessed through a tunnel.

A beautifully preserved and hidden 16th-century alleyway, tucked behind an unassuming door.

This whimsical statue dumps water on its head to symbolize knowledge flowing into his brain. Or maybe booze.

This narrow Ghent alleyway is an officially sanctioned street art tunnel.

This fairytale castle was built as a show of power but was nearly torn down thanks to its history of torture.

A giant bug impaled on a 75-foot-tall needle.

Where George Lemaître discovered the expanding nature of the universe.

A replica of a 17th-century map of the stars stands in the courtyard of a Belgian university.

This 19th-century zoological collection has withstood the test of time.

Above the door of a house, a plaque claims to commemorate the future living place of the inventor of time travel.

A whimsical bridge uses saxophones to pay tribute to two great men and the European Union.

Rare wooden escalators lead deep down into an otherwise staggeringly monotonous tiled tunnel.

According to this bar, God gave an “11th commandment” to Antwerp: Thou shalt drink beer.