Large, airy hallways hide within an impenetrable fortress that beckons urban explorers.

Yugoslavia's biggest underground airport lies in ruins.

This stunning, out-of-the-way Croatian monument commemorates a community's uprising against occupying fascist forces.

Where the lovelorn find a home for their sentimental keepsakes.

An ethereal glowing blue ocean cave in Croatia.

Columbus' failed colony in the New World.

An eccentric German artist built this weird and wondrous castle packed with shocking sculptures and alien art.

The first official clock in North America, it kept time for the Spanish government of Santo Domingo.

Renowned restaurant tucked in a cave once occupied by buccaneers.

Hundreds of pieces of ancient Taíno art cover the walls of this Caribbean cave system.

Perhaps the most spectacular grotto along the Algarve coastline.

Walk through spectacular aisles of hanging meat and wagon wheel–sized cheese at the world's largest wholesale food market.

Burbling away in refrigerators are 105 sourdough starters from around the world.

A giant pineapple, a symbol of hospitality, and an amazing vacation rental option.

Drink your espresso at a Victorian-era urinal in this underground-restroom-turned-coffee-bar.

The only runway directly into the magic kingdom has been closed since 1972, but it still sings to you if you drive fast enough.

This roadside stop between Goblin Valley is the perfect location to view some of the region's natural wonders.

A dazzling display of red rocks weathered into spires and hoodoos.

An Ancestral Puebloan ruin that appears to burst into flames in the sunlight.

One of the world’s largest collections of petroglyphs records 2,000 years of human activity.

This gallery of prehistoric red ochre art lines the wall of a scenic segment in Utah's San Rafael Swell.

Settled by the Church of Jesus Christ of Latter-day Saints in 1859, this abandoned frontier town has appeared in several films.

The marker offers a rare chance to be in four U.S. states at once, though there's some controversy over its geographic accuracy.

Come for the speed, leave in love with the desert.