Though it's thrived abroad, this forgotten Dunkin' rival has just one store left in the States.

This 1,300 year old monastery built atop a single rock was once only accessible depending on the whims of the tide.

The enormous 250-room Vanderbilt mansion conceals hidden doors and secret passageways.

Its collection commemorates the author of the iconic children's book "Heidi."

A communal oasis on Lake Zurich.

The steepest classic funicular in the world glides along a dizzying incline.

The tallest outdoor elevator in Europe rockets passengers on a dizzyingly precarious ride to the top of a mountain.

Today this former Nazi concentration camp stands as a poignant memorial to the victims of fascism, and a warning from history.

Now overgrown, these anti-tank barriers from World War II are sometimes called "dragon's teeth."

The former 1920s mansion of a prominent Catalan developer was used as the Soviet Embassy during the Spanish Civil War, and there is still a bunker below the garden.

A fitting attraction for the corn capital of the world.

See Hoover Dam and the bypass bridge from a perspective usually off-limits to the public, and float the upper part of the Black Canyon National Water Trail.

This platform is now a memorial dedicated to those who were deported during the Holocaust.

This 16-foot-diameter wooden coin has been standing in Iowa City since 2006.

Cemetery featuring rare glass-fronted columbarium.

A cable-suspension footbridge that hangs high above the Mill River.

Jule Körner's house full of bizarre architectural details.

Houses are tucked between, on, and underneath giant boulders.

A boulder in the Churchyard of Down Cathedral marks the legendary burial place of "The Apostle of Ireland."

Three playfully immersive mini golf courses let you travel alongside your ball to the cup at this facility, which has been around since the 1950s.

One of the last surviving C-97s sits in a field in front of a Wisconsin inn.

A historic observatory precariously perched at the "Top of Europe."

The Swiss artist's bulbous and overgrown shape-shifting sculpture controversially graces the center of Bern.

This airport currywurst stand is made out of retro airplane parts.