The 320-year-old tree that greeted General Lafayette and rerouted an interstate highway.

This rare triple-jurisdiction drawbridge passes through Virginia, Maryland, and Washington, D.C.

This historic lighthouse was well known for the large number of women who served as its keeper.

Home of the physician who set the leg of John Wilkes Booth after the Lincoln assassination.

Maryland's first (and last standing) toll house on America's first federal road established the state as the "Gateway to the West."

An isolated island home to one of the oldest English-speaking communities in the region and Maryland's state dessert.

Three abandoned missile silos are hiding in plain sight behind a suburban development in Maryland.

Remains of a historic fountain that was mysteriously lost in the demolition of a D.C. traffic circle.

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

The stone marker that Mason and Dixon placed at the eastern end of the famous north-south border they surveyed.

Politicians, bureaucrats, and military officers gathered in this field near the Capitol to settle their disputes with blood.

The Forest Service's surprisingly sophisticated collection of wildfire prevention art features America's most beloved bear.

Once America's tallest structure, now a Baltimore landmark.

This one-room cabin where the young colonel slept during the French and Indian War.

This beautiful stone arch bridge wasn't even expected to stand for one day, but people have been crossing it for centuries.

A labor of love built by local hang-gliding enthusiasts, this ideal launch spot was outlawed by the authorities and has since been largely abandoned.

A remote horde of architectural treasures fit for Indiana Jones.

This abandoned Victorian-style house was built in 1884.

A remarkable time capsule of American manufacturing deep in Maryland coal country.

Built by the patriotic residents of Boonsboro in a single day.

Live data is transmitted from the Atlantic coast to instantly recreate the ocean waves in this fountain at the NOAA headquarters.

A faded sign from the 1920s remembers Baltimore's resistance toward banning alcohol.

The longest escalator in the Western Hemisphere takes over three minutes to ride down.

Captain John Smith thought these cliffs were amazing in 1608 but sharks thought so 20 million years before him.