The towering figures were created from the cemetery's fallen old-growth trees.

An unassuming, powerful monument north of the U.S. Capitol bears witness to the resilience of Japanese Americans during a time of grave injustice.

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

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

This sandwich shop has a century-old elevator behind a sheet of plexiglass.

One of the largest artillery pieces in the world sits in a Washington D.C. parking lot.

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

Members of Congress have traveled between the buildings on Capitol Hill for a century hidden from tourists, press, and storm clouds.

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

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.

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

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

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

The span is crooked and made from two older recycled bridges.

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.

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.

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

A hoard of sky catalogs, astrophysical journals, even the works of Galileo and Copernicus.

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

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

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

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

Home to a vast and influential collection of Shakespeareana.