America's only nuclear missile silo open to the public.

These decaying bridges 1,000 feet high are a reminder of the skill it took to cross the Colorado Rockies by rail.

One of the few surviving Panama Canal steam shovels stands outside a tiny Colorado mining museum.

An annual festival celebrating Colorado's most famous frozen corpse.

This Colorado fire station has been in continuous operation for more than a century.

When zealous marijuana enthusiasts kept stealing the "Mile 420" highway marker, the State of Colorado got creative.

One of few remaining antique carousels with stationary animals in the U.S.

Once a lonely sentinel on the edge of the Great Plains, this rebuilt trading fort offers a glimpse of life on the Santa Fe Trail.

This marker identifies the location where three states converge.

The largest source of fossilized insects anywhere.

The highest point in Oklahoma used to be a lawless outlaw's paradise.

Two tall rocks sit at the center of this site, once the home of a large Ancestral Puebloan community.

The ancient dwellings of the Puebloans, located in the cliffs of majestic mesas.

The highest point in North Carolina and the United States east of the Mississippi River, Mount Mitchell is named after argumentative explorer Elisha Mitchell.

A ship that lived many lives under many names is now known merely as the "Ghost Ship."

This road in the Great Smoky Mountains was supposed to assuage a displaced community, but ended up a $52 million dead end.

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There's a 12-foot-tall replica of the Washington Monument hidden under a manhole nearby.

This 1,500-acre development hopes to be the Central Park of the South.

The largest earthwork effigy in the world.

A toxic ghost town sitting atop a massive coal fire.

Dodge prohibitionists and slide through the telephone booth in Crif Dogs.

This abandoned lighthouse looks like a rusting oil rig, but has managed to survive a number of storms.

These remote Florida islands have a history of sea turtles and sunken treasures, and one of the world's largest coastal brick fortresses.