The only National Monument ever to go missing for nearly 50 years then resurface in a dump.

These abandoned waterworks are crumbling into the Potomac River.

A historic estate packed with George Washington's heirlooms, and its own nuclear bunker.

A Spiritualist house of worship where believers communicate with the dead in the spirit world.

This charming colonial alleyway is one of the oldest continuously used residential streets in the U.S.

The Pentagon is so large that it was planned like a city, complete with internal highway infrastructure.

The little-known, 300-year history of the area includes former lives as a bustling tobacco port, parking lot, and industrial dump.

Right next to departures—how convenient!

The Pentagon sits on a former island that was in Virginia at low tide and D.C. at high tide.

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

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

This one-room cabin where the young colonel slept during the French and Indian War.

An obscure public service from the U.S. government that redeems burnt, moldy, and soiled old greenbacks.

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

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

Memorializing an American tragedy of massive proportions.

An abandoned stretch of highway, deteriorating next to the operational one.

This lovely picnic spot featuring thunderous jet landings is an aircraft spotter’s dream.

This stretch of beach along California's central coast is a busy highway for the largest seal in the northern hemisphere.

"Congress may voluntarily remain in session throughout the summer, in order that our Congressmen may be protected from the intolerable discomforts and dangers of the ordinary outdoor weather!”

A hidden gem on the lawn of the U.S. Capitol Building designed by landscape architect Frederick Law Olmsted.

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

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

One of the most influential presidents in U.S. history wanted only this plain, elegant monument as his lasting memorial.