A computer bug so primitive it was an actual insect.

The remains of Martha, the last known passenger pigeon, serve as a tool to educate about conservation.

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

A historic estate packed with George Washington's heirlooms, and its own nuclear bunker.

A traveling postal dog covered 48 states and more than 140,000 miles, and he lives on as taxidermy, patched up with a rabbit's foot and a pig's ear.

An atomic bomb-proof strongbox protects the U.S. Constitution from terrorists and thieves.

Housing the National Women's Party since 1929, this historic house is now a monument to the fight for gender equality.

Light bulbs, scrap wood, and tinfoil comprise this homemade throne of the gods.

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

The only Civil War battle in Washington D.C. took place near this highest natural point in the city.

A painfully obvious spy house sits right across the street from the Russian Embassy.

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

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

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

A Spiritualist house of worship where believers communicate with the dead in the spirit world.

This leafy estate is worth $18 million and is so grand it has two mailing addresses.

This lonely waterfront memorial to the men of the Titanic was erected by the "Women of America."

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

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

Fittingly, America's museum of architecture is itself a magnificently designed old building.

A nostalgic bibliographic gem.

A haunting tribute to pioneering photographer Clover Adams.

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

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