This nine-story building is the oldest standing skyscraper in D.C.

While most wind tunnels test scale models, the "Cave of Winds" was large enough for actual airplanes.

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

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

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

The preamble to the U.S. Constitution written entirely from vanity license plates hangs in the Smithsonian museum.

A tiny monument to the unsuccessful attempt by Thomas Jefferson to place the prime meridian in Washington.

When it comes to handsignals (and colonialism) rock always beats scissors.

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

This forgotten boat elevator was an engineering marvel in its heyday.

Architecture lovers won’t stop touching the National Gallery's 19.5 degree marble prow.

A historic arena where the Beatles played their first concert in the U.S.

This stately mansion, built in 1787 by America's first Secretary of the Navy, is rumored to be one of the most haunted buildings in Washington, DC.

Before Nixon, "watergate" meant canals.

This unacceptably tall building was the real reason for Washington, D.C.'s skyscraper ban.

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

This robust fence in front of a historic Georgetown home is likely made from hundreds of recycled Revolutionary War firearms.

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

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

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

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.

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

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