This innocent-looking townhome is actually a subway exit.

A clock set into the concrete outside a Manhattan jeweler has been telling time underfoot for over a century.

A quiet and contemplative oasis in the middle of New York's bustle and riot.

This seaside Italian village doesn't just look Escher-esque, it actually inspired the mind-bending artist.

One man's extraordinary topiary garden in a small South Carolina town.

This 1830s store is believed to be the site of Harriet Tubman's first stand.

A statue commemorate Tommie Smith and John Carlos's brave protest at the 1968 Olympics, a watershed moment for civil rights.

This sprawling museum holds one man's giant collection of real tanks.

Bubbling up from deep underground is the warm crystal clear water that fills the Warm Springs Pools, America's oldest spa.

The most historic church in Fairfax County played a role in the creation of the American Red Cross.

This former Cold War missile control site played an important role in the creation of GPS.

One of the oldest train stations still standing in Virginia played a vital role during the Civil War.

Thomas Jefferson's estate is home to hundreds of varieties of historic fruits and vegetables.

The final resting place of an unidentified revolutionary soldier sits behind a Virginia church.

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

This cannonball stands as a reminder of the final act of a fleeting governor amidst a revolution.

An out-of-place Air Force radar dome is all that denotes this park as a former missile launch site.

Outdoor exhibits explore the contributions of European, African, and indigenous peoples to American frontier culture.

The airport was once a Civil War battleground, and the earthwork defenses can still be seen today.

Born a slave on the Arlington estate, Parks dug the first graves at Arlington National Cemetery, and was buried there, too.

Conveniently located within binocular range of a nuclear bunker, the "summer camp" area was a painfully obvious spy house.

Once forgotten and built over, this historic Black cemetery now houses a poignant memorial.

Rowdy rebels fortified this home during the first popular uprising in United States history.

A lone historical marker off the highway and scattered debris are all that remain of this Cold War-era missile site.