They sort through millions of dollars worth of diplomatic gifts on behalf of the government.

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

People escaping slavery may have hidden inside a corpse vault.

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

A historic ruin just 20 feet away from a busy highway onramp.

A derelict bit of infrastructure from the canal that once ran through D.C. is landlocked in the heart of the city.

For 60 years, the academy had no permanent location until members voted Washington D.C. as its forever home.

A small triangle of DC grass is the final resting place of one of Sonny and Cher's songs.

A layered tribute to the work of mosaicist Isaiah Zagar.

Lady Liberty's first beacon of enlightenment is now displayed in a museum near the statue.

A restaurant on Staten Island showcases a different grandmother’s cooking every night.

This field of concrete was once an active defense site armed with nuclear warheads.

The well-preserved remnants of a bridge that once made up a WW1-era military railroad.

This twice-relocated "Usonian" home is among the smallest built by master architect Frank Lloyd Wright.

This little brick tunnel built by Confederate forces was used to conduct surprise attacks on the railroad.

The 72-foot giant escaped confinement in a large patch of mulch only to be reburied in the sandy shores of the Potomac River.

An astounding collection of medical specimens, including bits of President Lincoln.

The hidden offices underneath Memorial Bridge have been locked up since 1976.

There's a 12-foot-tall replica of the Washington Monument hidden under a manhole nearby.

The tomb was guarded by soldiers from both sides of the war, and some left their initials carved in the brick.

Depending on who you ask, this controversial treehouse is either a charmingly creative child's playhouse or an illegal encroachment on public land.

The discovery site of the "Capitalsaurus," the official dinosaur of Washington, D.C.

The country's oldest continually-operated mini golf course lies hidden in plain sight, eclipsed by one of D.C.'s most popular tourist attractions.

An extensive, if one-sided, history of U.S. law enforcement's war on drugs.