The largest cemetery in the American Southeast is a hidden gem near the heart of Atlanta.

Conjoined twins Daisy and Violet Hilton were stars of the vaudeville circuit.

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

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

There's an old indoor swimming pool hidden directly underneath the White House Press Briefing Room.

A three-story tower of books about Abraham Lincoln is one of the more unusual monuments to the president.

This unassuming passageway played a key role in one of the most important events in U.S. history.

The tunnel under the Capitol Building where Congress takes out its trash.

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

There just so happens to be a court even higher than the U.S Supreme Court: a basketball court in the building itself.

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

This groundbreaking 16th-century map is known as "America's birth certificate."

A nostalgic bibliographic gem.

100 years later, they're still down there.

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

A street in front of NASA's D.C. headquarters has been named in honor of the Black women who were essential to early spaceflight.

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

This stunning blue and gold room changed cities twice before becoming part of the Smithsonian.

Home to items never before seen by the public.

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

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

One of the best-selling bar bands in American music history is commemorated in their hometown's Five Points neighborhood.

The world's largest fire hydrant is supposedly tornado-proof.

I-95's Tijuana-style celebration of kitsch at the Carolina border.