Graffiti-covered ruins that were once part of a farm owned by a mental hospital.

The romance of early commercial flight still fills this Art Deco destination.

The oldest continuously operating fish market in the United States.

Home to items never before seen by the public.

Ruins from the Parthenon and petrified wood line the interior of one of the world's most famous monuments.

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

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

Those with a sharp eye can find the hidden image of a German Shepherd on the memorial's Mural Wall.

The first presidential bomb shelter was located in an old vault under the Treasury, connected to the White House via tunnel.

D.C. once had its own tiny rival to the New York Stock Exchange.

Was there a small "backpack nuke" hidden in the attic? JFK apparently thought so.

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

One of the last mosaic tile facades found in the city.

These four islands right offshore have waterfalls, colorful lights, fancy buildings, and a secret purpose.

The awe-inspiring ship from the golden era of cruising has an incomparable history and a reputation as one of the world’s most haunted places.

A faux European lane smack dab in downtown L.A.

Giant Redwood-themed cafeteria operates under the golden rule, "Dine Free Unless Delighted."

A music-filled, booze-soaked oasis in the desert.

Version of the French Riviera destroyed by the sea.

An off-grid art installation that encourages its visitors to imagine a world without waste.

This abandoned Navy base was transformed into an off-grid alternative living community for thousands of people.

A hand-built folk art installation covered with messages of God's love.

The ghostly remains of an accidental sea.

This conservation area is also home to many of the region's desert tortoises.