High atop a Mexican rainforest mountain, this ancient pyramid once drew pilgrims countries away.

Cave where bat-eating snakes hang down from the ceiling.

This beautifully deceptive waterfall is something far different from what it appears to be.

Twelve natural mummies are displayed in the crypt of this former monastery school.

A jaw-dropping "megalibrary" that turns book-browsing into a geometric adventure.

Frida Kahlo's childhood home, now a museum of her life and works.

These azure waters were thought to lead to the Mayan Underworld.

A lovers' beach, tucked below the surface of the island, provides a safe haven for romance.

Native American burial mounds? Giant gopher dens? No one knows what created the Mima Mounds.

The longest continuous lava tube in the continental U.S. offers 2.5 miles of dark explorations for the adventurous.

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

The solemn exterior conceals an opulent interior of this 17th century church.

A neo-Gothic church built to thank God for saving the Emperor of Austria from an assassination.

An exquisite Baroque church in Vienna's old town.

The Habsburgs' royal collections of art and wonders.

Built to give thanks for the passing of a plague epidemic, this cathedral is a one-of-a-kind architectural hybrid.

The topiary maze at the Habsburg hunting lodge.

A tropical paradise just a short trip from the opera house is filled with beautiful winged creatures.

An alien landscape of chalk-rock in the Egyptian desert.

An ancient instrument used to measure the waters of the Nile so Egyptian farmers would know whether to expect famine or flood.

A collision of human error and natural geothermal pressure created this rainbow-colored geologic wonder.

Central City celebrates its most famous madam by racing beds down Main Street.

Giant pinnacles in the sun-scorched lands of Southern Utah have been nicknamed "white ghosts."

One man has installed bathtubs into the Utah desert floor to harness the powers of a natural hot spring.