This massive subterranean fissure is known as the "underground Grand Canyon."

Castle and secret tunnel withstood a siege until its owner was killed by the Holy Roman Empire, while sitting on the toilet.

This picturesque monastery at the base of a cliff is a peaceful oasis open to all visitors.

Oriental bazaar in the heart of Sarajevo.

This abandoned Olympic skiing facility still bears the scars of the Siege of Sarajevo.

A war-torn Olympic relic is being overtaken by graffiti and nature.

There's a mini version of Iguazu Falls hidden in the Balkans, and it's got a rope swing.

Bridge that died in war and was resurected.

After a short-lived attempt to bring America in line with the rest of the world, this road was left in metric.

One of the most extensive and well-preserved collections of dinosaur footprints in North America.

Some of the tallest ancient American ruins continue to inspire awe and curiosity.

Ancient pueblos built into the base of a natural canyon wall.

America's only nuclear missile silo open to the public.

See massive fossils that are over 200 million years old in northeastern Arizona.

This 4,000-foot-diameter hole is touted as "the most well known, best preserved meteorite crater on Earth."

Ninety feet off the valley floor is an ancient dwelling put under protection of the U.S. government by Teddy Roosevelt.

Dramatic river bend surrounds a natural red-rocked pedestal.

Most-visited and most-photographed slot canyon in the American Southwest.

Intricate metal sculpture that's half gothic cathedral, half construction equipment.

Brussels' favorite peeing boy has a sister.

A fantastical 13th-century fortification sandwiched by a modern hotel in central Brussels.

A little sculpture with a large wardrobe.

Theme park featuring miniature replicas of European monuments.

Cozy basement bar sports an inventory of over 2,000 beers.