Home to the deepest rift anywhere on Earth.

Native Americans built this circle of stones, which was used to predict astronomical events.

The first declared National Monument in the United States.

This erect, phallic geological spire wasn't always named so domestically.

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

This small piece of railroad history sits behind the parking lot of a chain grocery store.

The scene of one of the darkest moments in American labor history has been left essentially untouched since the tragedy.

The Grand Canyon of Texas.

The western face was supposedly left clock-less to snub the Welsh.

This striking observation tower shaped like a spinnaker sail is the newest icon in historic Portsmouth.

This star-shaped artillery fort protected the mouth of the Thames from the 16th century to the Second World War.

The castle still holds traces of the abandoned Roman fort it was built atop.

This single room has survived the centuries with almost no deterioration.

An antique horse-drawn hearse provided French luxury for the dead in this Texan town.

Colorful curls of hand-blown glass form a captivating tower in San Antonio's Central Library.

The story behind the mysterious symbol painted in front of the historic university's famous Rotunda.

This iron and wood Civil War city-ship was the first vessel to be sunk by an electrically detonated torpedo.

An eerie and beautiful group of columns mark the site of a grand mansion lost to time and fire.

A grandiose octagonal home crowned by a large dome stands out among the antebellum mansions.

A remarkable medieval structure born from a 14th-century disaster.

Strange red rock formations that have been attributed to a higher power for hundreds of years.

Cryptic messages embedded in the New York City sidewalk.

This big empty pig is a nostalgic throwback to mid-20th-century Texas barbecue.

A unique tribute to the millions of animals who served and died for the British military.