The oldest surviving one-room schoolhouse in Montgomery County, Maryland.

Using a massive antenna made up of five miles of wire, two scientists tuned into organic radio waves from the planet Jupiter.

Dating to 1793, this is the oldest building in Poolesville.

This university transit system is a 1970s vision of the future.

Once the center of a thriving early Black community called Martinsburg.

Built in 1815, the stabilized ruins of the grist mill and sawmill are now gated, but interpretive displays on the features and functions of the mill preserve its history.

Built in 1945, this historic train station has a new lease on life with its baggage area serving as an event space.

The word "Watergate" will forever be associated with the infamous scandal in 1972, but this fountain is famous in its own right.

Long buried under the 20th-century landscape, this lift lock of the Alexandria Canal is the lone remnant of an ambitious early American transportation project.

This bell is one of the last remnants of the lost city of Triadelphia.

The only public swimming pool in Baltimore open to Black Americans during segregation is now a permanent memorial art exhibit.

The penultimate and final resting places of British General Edward Braddock—minus a few bits and pieces.

With over 100 jam-packed rooms to explore plus elaborate tea services and events, the Mansion on O Street is a hidden treasure.

Franciscan monks created a facsimile of the Holy Land for North Americans who couldn’t afford the trip overseas.

Mysterious rocks that ring musically when struck.

Home of an evil witch famous within southern folklore.

The Corinthian columns that towered over Abraham Lincoln’s inauguration stand proud.

A toxic ghost town sitting atop a massive coal fire.

The headquarters of the Audubon Naturalist Society is a small slice of heaven for nature lovers.

Home to what was once considered the largest gate in central Asia.

The heartbeat of modern Uzbekistan’s thriving market culture.

The rocks are a time capsule of a 407-million-year-old Earth.

Beautiful palace stands tall over the Fergana Valley.

Touching displays of wishes for peace from the Cold War era.