This seemingly out-of-place gas station by the Watergate hotel was once described as the most expensive gas station in the world.

A three-story tower of books about Abraham Lincoln is one of the more unusual monuments to the president.

Before Metro, Washington had a robust streetcar network—and you see the remains of this infrastructure if you know where to look.

While most wind tunnels test scale models, the "Cave of Winds" was large enough for actual airplanes.

This robust fence in front of a historic Georgetown home is likely made from hundreds of recycled Revolutionary War firearms.

The national park was once a plantation estate.

The "lovely red Vega" of the legendary record-settling pilot.

The house where John Wilkes Booth conspired with his co-conspirators.

The country's oldest continually-operated mini golf course lies hidden in plain sight, eclipsed by one of D.C.'s most popular tourist attractions.

Enormous piles of historically significant stones, dumped by Congress in a forest, and abandoned for 60 years.

A tiny piece of the Moon is embedded in this stained glass masterpiece.

More than 5,000 contemporary and "historic" mustards from around the world.

This soda factory is one of the last in America to use real cane sugar despite the protestations of Dr Pepper.

Coca Cola may be "the real thing" but its inventor, buried at this Georgia gravesite, called it a "valuable brain tonic."

While many places make the claim, the Library of Congress says this restaurant is the birthplace of the hamburger.

A World War II-era submarine is stuck in the mud in New Jersey.

A reminder to choose water over wine since 1888.

Permanent exhibit reminds visitors of the Exxon Valdez.

Just like the real 36th president of the United States, animatronic LBJ amuses visitors with jokes and stories.

A line of blue paint marks the route of the inaugural parade.

One of two side-by-side totem pole parks dedicated to educating visitors on Tlingit history and culture.

The whole world in one water tank.

A morbid gateway to an Alaska town prides itself on the hunting history it represents.

The summer home and later final residence of acclaimed American sculptor Augustus Saint-Gaudens.