Once one of the world's great cities, Cahokia was a place of religious worship, trade and mass human sacrifice before being mysteriously abandoned.

Four glass boxes hover over 1,000 feet in the air to give visitors an unparalleled view of Chicago.

Some of the tallest ancient American ruins continue to inspire awe and curiosity.

See massive fossils that are over 200 million years old in northeastern Arizona.

A self-built castle made by a mysterious man.

This small shack near the entrance to Sequoia National Park has been in almost continuous operation for the last century.

One of the most elaborate displays of Jellyfish is on display at the aquarium.

An elaborate gift from Claus Spreckels is now a piece of San Francisco history.

Haunting and beautiful trees, doomed to die.

An historic and oft-filmed spot for musclebound iron pumpers on the Pacific coast.

Once close to extinction, there is no shortage of elephant seals on the beaches of Año Nuevo State Park.

One of the oldest producers of hand-folded fortune cookies still uses its original secret recipe.

Rodin's famous depiction of Dante's 'Inferno', amidst a sculpture garden of many of his other works.

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.

A collection of 20th-century automata, penny arcade games, and musical contraptions.

Staircase winds down the side of Telegraph Hill through gardens, wild parrots flying overhead.

One of the most scenic stretches of road in America winds between some of the country's oldest trees.

Quite simply the largest tree in the world (by volume).

San Francisco's newly reopened hands-on science museum.

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

This strange seaside tower got its name from a wealthy eccentric who would hide coins among its stones.

A building so large that it has its own weather.

Enjoy dishes that founding fathers once ate at this Colonial Williamsburg pub.