This fort down the Potomac from Washington, D.C. was once the only defensive fort protecting the capital.

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

This scenic Maryland park was the site of one of the worst prison camps of the Civil War.

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

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

One of the only memorials dedicated to journalists who died in combat.

The world's oldest continuously operating airport was founded by the Wright Brothers.

A mammoth pair of Civil War artillery guns abandoned out in the forest.

This 16-foot, intricately detailed model of the Gearing-class destroyer has been called the most detailed model ship ever built.

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

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

The bridge's highly-contested plaque (once again) honors Confederate President Jefferson Davis.

A relic of FDR's brief foray into utopian urban planning.

A winding district gerrymandered into the shape of a mantis.

A Maryland museum dedicated to Black history, housed in a historic church.

FDR's Art Deco hospital tower was hopelessly inefficient.

The childhood home of the Sultan of Swat is just a line drive away from Oriole Park at Camden Yards.

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

Largest Roman Catholic church in North America.

This imposing Masonic temple a mile from the White House was the first public library in Washington, D.C.

The actual model from the original "Star Trek" series is now on display at the National Air and Space Museum.

It was once the base for a series of domestic terror attacks.

When it opened during the final years of the embargo, all the drinks and cigars were free.

Government testing at the asylum briefly explored using marijuana as a "truth serum" on Nazi prisoners of war.