America's most famous museum of medical oddities is home to the remains of Albert Einstein's brain.

Hidden behind West Philadelphia rowhomes is a haven for migratory and local bird species both ordinary and rare.

The oldest of only three existing statues of the great novelist stands in a city he did not care for.

A benevolent, 16-foot-tall river dragon lives on a suburban lawn.

An intricately designed junk art house with four extravagant junk art cars hidden in the suburbs.

Once the supplier for noteworthy projects like the National Cathedral, this old brickworks now lies abandoned.

Art deco landmark on the outskirts of Washington, D.C.

A spectacular tribute to statesman and philanthropist Andrew Mellon.

A muscular Art Deco monument represents the struggle between regulators and unbridled markets.

An echo chamber with a waterfall wrapped around its base at the Embassy of Canada in Washington, D.C.

A much-maligned monument to teetotalism.

During the Industrial Revolution this “Temple of Invention” was full of intricate miniature machines and gadgets.

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

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

This unacceptably tall building was the real reason for Washington, D.C.'s skyscraper ban.

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

There's a crumbling old mansion inside the Smithsonian National Zoo.

A surprising, but overlooked example of geology in the middle of the nation’s capital.

One of the oldest active carousels in the country—but it might be missed by all but the keenest-eyed boardwalk strollers.

This isn't your average roadway—it's actually a National Park and a transportation pioneer.

An amazing example of early-20th-century architecture, this church features marble transported from Utah.

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

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

Washington's iconic carousel has a nice piece of Civil Rights history.