This cannon dating to 1755 has stood guard at this suburban intersection since 1915.

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 small pedestal marks the spot of the first lot of land sold in Alexandria, Virginia in 1749.

Named for a Greek oracle that interpreted the words of Zeus, this beautifully-restored manor home was once home to the architect of the Marshall Plan.

George Washington once stopped by this house for dinner.

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

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

The former home of the woman who successfully fought to integrate restaurants in Washington, D.C.

Washington D.C.'s most famous pianist, composer, and bandleader still tickles the ivories outside Howard Theater.

The former home of Lillian Evans Tibbs and her grandson, Thurlow Evans Tibbs Jr., whose prodigious contributions to music and art spanned more than 90 years.

In this cemetery stands the country's first public crematorium.

The first of Lancaster's "rural cemeteries."

The oldest farmer's market in America is so ancient it was approved by the King of England.

The home of possibly the least-loved U.S. president stands as a sort of unpopular Monticello.

An outlandish shoe shaped house built by an eccentric millionaire.

This Georgian-style house built in 1746 is the oldest surviving structure in Bladensburg.

This historic boathouse was constructed using salvaged lumber from burned barns.

The only road through the heart of Glacier National Park.

This shale formation along the Appalachian Trail once inspired the third president of the United States.

A superbly preserved example of Georgian residential architecture that was once home to one of the founders of Alexandria, Virginia.

Recorded as the first person buried in Arlington Cemetery.

The only U.S. Senator to die on the field of battle is buried in San Francisco but memorialized at Balls Bluff Regional Park.

This "castle" is actually a limestone and quartz formation hidden along a trail.

The former home of Dr. E.B. Henderson, also known as the "Father of Black Basketball."