America's Most Wanted's set resides in this tribute to the history of crime and punishment.

It was once the base for a series of domestic terror attacks.

A hidden passageway now marks the site of an assassination attempt on Ronald Reagan that some say broke a 140-year-old curse.

This unassuming passageway played a key role in one of the most important events in U.S. history.

The preamble to the U.S. Constitution written entirely from vanity license plates hangs in the Smithsonian museum.

Sit where JFK proposed to Jackie or where Nixon dined on meatloaf at this storied pub.

The "lovely red Vega" of the legendary record-settling pilot.

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

Decades before the scandal, this staircase on the river was a literal "water gate."

The house where John Wilkes Booth conspired with his co-conspirators.

Government testing at the asylum briefly explored using marijuana as a "truth serum" on Nazi prisoners of war.

An Industrial Revolution-era public work that purified water using nothing but sand.

A nostalgic bibliographic gem.

The walls of the iconic dome are hollow and have a secret stairway.

People escaping slavery may have hidden inside a corpse vault.

The winding route passes through an enclosed alleyway, two tunnels, and leads to the White House basement.

A cavernous three-story, 43,800-square-foot basement that was forgotten about for 60 years.

A monument in Washington D.C. marks the spot from which all other roads were supposed to stem.

A historic neighborhood church is reborn as a psychedelic arts collective.

This mountain sunrise is one of the most breathtaking views in Thailand, yet well off the tourist trail.

On a river island north of Bangkok, a small bar helped lead a home-brewing rebellion.

Buddhist university that allows English-language speakers the opportunity to study with monks in Thailand.

Buddha shrines hide within dark tunnels at this unique forest temple.

The long underground cave's curiously shaped stalagmites have inspired many legends.