One of the world's tallest waterfalls wasn't revealed to the world at large until 2006.

A remarkable geological formation resembling a forest made of stone.

Preserved Inca city and site of the last Inca stronghold against the Spanish conquistadors.

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

The mortal remains of an estimated 70,000 people lie in the basement of a monastery in Lima, Peru.

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

Keshwa chaca, among the last handwoven Incan bridges, crosses Apurimac Canyon in Peru.

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

San Francisco's urban bison herd has persisted in the face of extinction, development, and disease.

A 300-ship graveyard, with a few still visible at low tide.

A nondescript building that's been functioning as a speakeasy for nearly a century and a half.

The seawater playground of gilded-era San Francisco burned to the ground in 1966.

A pair of slides and a tree-lined stair corridor have been an urban oasis for nearly 40 years.

Relics of the 1894 Midwinter Exposition continue to delight visitors today.

A winding path built in secret on the edge of the continent.

An artsy hidden staircase leads to breathtaking views of San Francisco.

A psychedelic labyrinth on the San Francisco bay.

Travel deep inside of Europe's second largest glacier in the world's largest man-made ice cave.

The oldest steel ship in Iceland has been beached for years and is now a rusting ruin.

The summer tourists on these cliffs are thousands of seabirds.

Three million year old fossils are exposed for all to see on this Icelandic shore.

A sulfuric martian landscape that looks far better than it smells.

This mountain fissure hides a secret path to a secluded mossy grotto within the rock itself.

This tumultuous Icelandic lava field looks so alien European researchers want to use it as a stand-in for Mars.