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

The bank that helped fund the Mexican-American War and the purchase of Alaska met its downfall after helping Augusto Pinochet launder money.

A line of blue paint marks the route of the inaugural parade.

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

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

The most decorated dog of World War I is preserved in the Smithsonian.

Perhaps the most scandalous statue of America's first president.

This stunning blue and gold room changed cities twice before becoming part of the Smithsonian.

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

The actual model from the original "Star Trek" series is now on display at the National Air and Space Museum.

Rumor has it the uncarved lump behind the three famous suffragists is reserved for the first woman president.

A little marble compass above George Washington's (empty) tomb in the Capitol marks where D.C.'s four quadrants intersect.

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

A promising candidate for the lost rock laid by George Washington was unearthed, but the hunt is still on.

Senators used to relax in the nearly forgotten marble tubs now hidden in the U.S. Capitol Building's basement.

The elevator that makes it possible to fly American flags in bulk over the U.S. Capitol

"Congress may voluntarily remain in session throughout the summer, in order that our Congressmen may be protected from the intolerable discomforts and dangers of the ordinary outdoor weather!”

A hidden gem on the lawn of the U.S. Capitol Building designed by landscape architect Frederick Law Olmsted.

One of the first Second Empire-style buildings constructed in North America.

Largest Roman Catholic church in North America.

This house was the subject of an Edward Hopper painting, which in turn helped inspire the design of the Bates house in Alfred Hitchcock's 'Psycho.'

A retired subway car stands alone in a field in the middle of Queens.

In Houston's airport, a cow is properly equipped to jump over the moon.

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