Moss and stone turn this waterfall into an otherworldly liquid veil.

A 300-yard long natural tunnel runs through a ridge deep in the Appalachian Mountains.

This beautiful natural train tunnel is said to grant the wishes of visiting lovebirds.

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

Iran's colorful terraces are a rare geological masterpiece.

This abandoned fishing settlement may well be the greenest village in the world.

This scalding hot river was thought to be a myth until one geoscientist made it his quest to study the mystical waters.

Roman ruins top white travertine terraces formed by ancient hot springs.

Abandoned railway line circling the city of Paris.

This Scottish bridge seems to compel dogs to leap to their death.

A remote candy-striped mountain in the Peruvian Andes straight out of the pages of Dr. Seuss.

The villagers of the coldest inhabited place on Earth adjust to unique challenges presented by day-to-day living.

The centuries-old trees lining both sides of this dirt road may become Madagascar's first natural monument.

The once forbidden "secret cabinet" of erotic art from excavations of Pompeii and Herculaneum.

The hidden "ballroom" under a mansion lake was built by a criminal who ate a cyanide pill during his trial.

This historic stone bridge has an entire neighborhood clinging to its sides.

Rome's semi-secret peephole vista is also a former Crusader stronghold.

This jaw-dropping 19th-century bridge uses its reflection to form what appears to be a perfect circle.

Walk behind a 50-meter-high waterfall.

An incredible menagerie of more than 3 million taxidermied animals at the oldest science museum in Europe.

An exquisite tunnel of cascading flowers.

In this truly magical place, rent hasn't been raised since the year 1520.

This everlasting lightning storm may be the world's largest generator of ozone.

This quaint Italian town keeps losing ground as the sides of its plateau slowly erode.