Recorded as the first person buried in Arlington Cemetery.

The tallest church in Mechelen might have been the tallest in the world if not for a lack of funds.

One of the first Second Empire-style buildings constructed in North America.

Now a living classroom, this house was once the home of Reverend James Clinton Dent, a formerly enslaved man and a pastor.

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

This grand Spanish-Cuban restaurant has been serving customers for more than a century.

Home to two notable early-20th-century Black educators, Lucy Slowe and Mary Burrill.

A massive white oak tree provides a beautiful canopy near a suburban shopping center and stood before the signing of the Constitution.

Get up close and personal at this Fresnel Lens.

This general store has stood in the same spot for well over a century.

This environmental engineering marvel keeps salt water from the Elizabeth River.

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

A lightship turned museum, outfitted with artifacts from the vessel's past as part of the U.S. Lighthouse Service.

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

A memorial to legendary newsman, publisher, and owner of La Gaceta, the only trilingual newspaper in the U.S.

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.

This one-room schoolhouse was revitalized in 2007 as a museum focusing on the education of Black children during the early 20th-century.

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

First built around 1848, this bridge was destroyed by arson, but original timbers are included in the replacement.

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

This marker at the entrance to the Humphreys Engineer Center honors the former Chief of the Army Corps of Engineers.

Washed out by the Johnstown Flood in 1889, the surviving portion of the original two-span bridge now resides at Fishing Creek.

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

This mighty white oak in Bethesda survived both the American Revolution and the construction of Washington D.C.'s metro red line.