Where the U.S. government kept its actual treasure, before Fort Knox.

In the basement of the U.S. Capitol Building is a hidden storage room full of ornate floor tiles leftover from the 1850s.

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

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.

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

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

The privately owned cemetery that holds room for Washington's finest when they step down from life.

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

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

This unique museum cafeteria showcases the history and regional diversity of African American cuisine.

The unique traffic pattern named for an influential urban planner is also known as the Pedestrian Scramble.

Sit where JFK proposed to Jackie or where Nixon dined on meatloaf at this storied pub.

An overlooked oasis of quiet on the grounds of Washington's monumental basilica.

A clone of a cloned tree that was so important it allegedly had its own guards.

The institution is sitting on a goldmine of 21,000 paints, varnishes, pigments, and primers preserved for posterity.

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

Seemingly unremarkable items like empty sushi trays, chef hats, and freshness stickers are being preserved so future generations can look back on this beloved cultural import.

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

An easily overlooked memorial to a Ukrainian famine-genocide that killed over 4 million people.

The most accurate timepiece in the world.

These recently uncovered walls are all that's left of Washington, D.C's first defense contractor.

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

This restaurant has been a haven for D.C.'s LGBTQ community since the 1950s.

D.C.'s first central library was born out of a chance encounter with the philanthropist whose name it bears.