Volcanically heated hot springs.

This staircase full of Mayan hieroglyphics is perhaps the largest single text in the world.

Mesoamerican monoliths and zoomorphic stones covered in royal visages, ancient mythology, and grand celestial events.

Hidden deep in the Guatemalan jungle is a turquoise paradise of natural pools, caves, and waterfalls.

A devastated ruin in the south of Belize where British explorers claimed to unearth the Mitchell-Hedges Crystal Skull.

The ruins of an ancient Mayan city, beautifully preserved and only accessible by boat.

The enigmatic and seldom visited ruins of a Mayan city-state.

An elaborate Mayan city shrouded in alien conspiracy revealed the tomb of Pacal the Great.

A hidden treasure of an abandoned city lies deep in the jungles of Campeche, Mexico.

Every equinox this Maya pyramid puts on a spooky ancient light show.

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

This natural Icelandic fissure allows divers to swim right between two volatile tectonic plates.

This giant boulder is pinched over a 1000-meter abyss by two mountains.

Mother Nature outdoes herself with this stunningly beautiful set of caves carved into marble.

If you can look past the nearby sewer pipes, this urban sinkhole grotto is a mini-paradise.

Iceland's "Smoky Valley" is a beautiful river that is shrouded in a constant cover of steam clouds.

A magically clear, blue river that seems to spring from nowhere.

An Italian crevasse filled with abandoned buildings gives visitors a look at the world without humans.

A graceful natural rock formation stands astride the point where the Gulf of California meets the Pacific Ocean.

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

Even Henry David Thoreau found this glacial pothole irresistible.

A massive underwater sinkhole made famous by Jacques Cousteau.

The most powerful waterfall in all of Europe.

This valley of hot springs and boiling mud pots is home to the record-holding "Geysir," which originated the English word.