This spectacular track has run continuously since 1882.

The superstar of Cold War nuclear bunkers has been featured in countless films but is now barely operational.

When ecosystems collide in the arid Southwest.

The highest bridge in America was built for an almost unnervingly small amount of money.

The largest self-built castle in the U.S., six decades in the making.

A breathtaking array of ancient Pueblo structures and artifacts counterintuitively preserved by neglect.

This modern antique shop is a museum for 1980's Saturday morning cartoon culture.

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

Paranormal experiences in this hotel's room 217 led Stephen King to write "The Shining."

Wondrous sandstone hoodoos where Native Americans collected clay for pottery, 9,000 years ago.

Crystal clear lake with a shoreline of travertine located in a Colorado canyon.

This was once the home of Gahan's Saloon, Denver's most storied speakeasy.

Once a mortuary that held the remains of Buffalo Bill, this Denver hotspot is now a death-fixated restaurant.

This replica of the Greek structure is in the heart of Nashville.

Victorian-era Egyptomania left its mark on this Nashville landmark.

At 135 years old and counting, this historic print shop is heaven for poster nerds and music buffs.

An abandoned cemetery lies in ruins as the surrounding forest swallows it whole.

This historic lighthouse was well known for the large number of women who served as its keeper.

One of the oldest log cabins in America is one of the last of its kind this historic Swedish dwelling remains a piece of living history.

Pennsylvanian mass grave and possibly mass murder.

North America's oldest quarantine facility was built in response to Philadelphia's 1793 yellow fever outbreak.

A rural colonial settlement that contains the remains of a store and cooper.

A scenic fort on the harbor protected Philadelphia from an attack that never came.

This splendid Versailles-inspired mansion has the largest French-style formal gardens in North America.