Go take a picture with the inventor of the daguerreotype photographic process.

A fantastic array of trays and cables once whisked books over to the Capitol at 600 feet per minute.

Senators used to relax in the nearly forgotten marble tubs now hidden in the U.S. Capitol Building's basement.

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

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

Legend has it that President Grant’s frequent drinking in the lobby gave rise to the term “lobbyist.”

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

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

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

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

This poor little statue is the most vandalized memorial in Washington.

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

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

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

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

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.

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

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

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

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

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

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

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

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