Dramatic river bend surrounds a natural red-rocked pedestal.

A massive underwater sinkhole made famous by Jacques Cousteau.

An ancient capital city that dates back 3,000 years old and harbors many surprises.

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

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

The neon signs from Las Vegas' past find their final resting place at this unusual graveyard.

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

A church of bones, decorated with 40,000 human skeletons.

The ghost town left by the worst nuclear disaster of all time is being taken over by nature and urban explorers.

The intricate stonework of Machu Picchu serves as a testament to Incan engineers.

World's first "penitentiary," meant to be humane, drove men insane.

An emerald-green grotto just a short trip from Austin.

This astonishingly geometric cave has inspired everyone from Jules Verne to Pink Floyd.

During prohibition, corrupt city officials ran drinking dens under the streets of Downtown Los Angeles.

A beautiful and abandoned New York subway station from 1904, complete with chandelier.

A peculiar mansion built by the troubled heir to the Winchester Rifle Company fortune.

A seemingly endless landscape of pure salt stretches far across Bolivia.

This huge pile of volcanic boulders hides a stunning network of secret grottoes.

This tiered waterfall is so pretty it may cause visitors to cry tears of their own.

A naturally beautiful, seemingly bottomless deep blue spring.

An Australian lake whose pink hue defies scientific explanation.

The 1936 Summer Olympics site is a crumbling remnant of sportsmanship and a history its host country would like to forget.

A former top secret nuclear fallout shelter now operates like a hotel stuck in the Cold War.