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

A wondrous old library overlooking the nation's capital.

The beloved statue at the National Academy of Sciences is oh so inviting to sit on.

This stately mansion, built in 1787 by America's first Secretary of the Navy, is rumored to be one of the most haunted buildings in Washington, DC.

Helen Keller once broke ground on this historic center for the study of technologies to benefit the hearing impaired.

When it comes to handsignals (and colonialism) rock always beats scissors.

You could be standing at the site of one of D.C.'s most fatal tragedies and not even know it.

The first purpose-built art gallery in the United States is once again open as a center of craft arts.

People escaping slavery may have hidden inside a corpse vault.

Four bald cypress trees in Lafayette Square, across from the White House, mark the southern edge of a 100,000 year old cypress swamp.

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

With over 100 jam-packed rooms to explore plus elaborate tea services and events, the Mansion on O Street is a hidden treasure.

Obscure Freemasons still live in D.C.’s largest private residence.

Long-abandoned trolley tunnels just a mile away from the White House are turning into an art space.

A rotating cast of guys and dolls in front of a Washington, D.C. building.

Daily lunch spot for many of Washington, D.C.'s cab drivers.

The quirky collection includes treasures like Elvis' underwear, Bob Barker's toothbrush, and hundreds of sock monkeys.

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

A mental health hospital dating back more than 139 years, now features a museum.

A museum of natural history, Edwin Carter's original log cabin home and workshop houses taxidermy specimens.

This statue of an obscure comic strip hero stands as a tribute to patriotic service and a cautionary tale about embracing fads.

Birds with backpacks expedite film development for a rafting company on a remote Colorado river.

The burial grounds of a secret society includes fences topped with fake Tesla balls.

Hidden high on a remote mountain peak is a humbling and mysterious Vietnam War memorial.