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

The last remaining relic of San Francisco's glittering 1915 Panama Pacific Exposition.

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

In all of the 29 years it was in operation, no prisoners ever escaped successfully... or so they claim.

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

No telescopes, no power, no gift shop: The Observatory of Chichen Itza, one of the world's oldest observatories, takes astronomy back to basics.

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

Diego Rivera hid various people and symbols in his first large-scale mural project.

These roaring primates were considered a divine creature in the cosmology of the Maya.

Deep in the Guatemalan jungle stands an ancient pyramid that once marked the reign of a king.

An important Mayan religious and trading center dating back to 200 BC.

From a distance, Latin America's first Baha'i Temple looks like an enormous egg perched atop a hill.

A museum dedicated to the German scientist who revealed the significance of the mysterious Peruvian Nazca Lines.

Built on the remains of one the Incas’ most important gathering spots, this square keeps the spirit of a fallen empire alive.

Situated on a sacred Inca site, this 16th-century cathedral took nearly 100 years to build.

The sophisticated hydraulic system of the Nazca civilization.

On this tiny spot of land in the middle of Lake Titicaca the only ones who do the knitting are the men.

This geometric feat is a testament to the Incas' mesmerizing architectural abilities.

This metal tower in the desert provides views of a handful of Nazca geoglyphs.

The mysterious "Candelabra of the Andes" could represent anything from a god's trident to a hallucinogenic plant.

This stone complex marks the urban center of a lost civilization.

The Uros people live on floating reed islands in lake Titicaca.

The stones of this Incan wall complex fit together so well you couldn't fit a piece of paper between some of them.

Death rituals and sacrifice inside a Peruvian megalith.