A psychological self-portrait in the form of a giant, segmented head.

A comprehensive collection of Pez dispensers.

After the attack on Pearl Harbor, rocks and fossils from every U.S. state were collected into a pyramid of national unity.

A whimsical, punny collection of "fence art" outside the tiny mountain town of Baker, Nevada.

A petroglyph map of the upper Snake River carved by prehistoric hunter-gatherers.

Members of Congress have traveled between the buildings on Capitol Hill for a century hidden from tourists, press, and storm clouds.

The first presidential bomb shelter was located in an old vault under the Treasury, connected to the White House via tunnel.

100 years later, they're still down there.

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.

The Pennsylvania landscape depicted by a quarter mile of mosaics made from used road signs.

The old Route 66 town straddling Texas and New Mexico died along with the Main Street of America.

One of the largest-ever mental hospitals now sits abandoned, surrounded by 25,000 unmarked graves.

A magical work of architecture where a wind turbine enables monks to levitate.

This massive geographical sculpture is so subtle, it's possible to pass by it without noticing.

The artist James Turrell is repurposing an extinct volcano crater as an observatory to experience the cosmos.

In the remote high desert of New Mexico, a strange array of poles beckon fury from above.

A sculpture for the sun and stars, created by Nancy Holt.

Michael Heizer's masterwork in the Nevada Basin.

One man has carved a number of natural New Mexico caves into psychedelic sandstone temples.

A mistaken marker makes an erroneous claim along the historic Old Divide Road.

Where the Model T was made and the assembly line was invented.

Weighing 30,000 pounds, this monument represents Detroit's first industrial era.

What was once the largest NFL stadium.