The Pentagon is so large that it was planned like a city, complete with internal highway infrastructure.

One of America's first spies started out as a teacher in this little red one-room schoolhouse.

Memorial to one of the most fatal fires in both circus and U.S. history.

This strangely amalgamated museum explores the history of the Timex clock company as well as archaeology.

Public outcry led to this bridge's unique character which celebrates a giant frog battle and also sewing.

An abandoned gun-funded 19th century utopia.

This abandoned psychiatric hospital once housed more than 4,000 patients in the middle of a quaint New England town.

The oldest place in Hartford is a cemetery with thousands of bodies stacked beneath the grass.

Final resting place of a New Haven urban legend.

Holding multiple historical boats and an entire 19th century village, this New England attraction is the largest maritime museum in the world.

The ancient past meets the retro-future at these dinosaur tracks that are protected by a geodesic dome.

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

The former home of Samuel Clemens and family remembers the happiest period of the author's life.

A reliquary of pop culture marvels, including the world's largest (and most terrifying) Jack-in-the-Box.

This lovely picnic spot featuring thunderous jet landings is an aircraft spotter’s dream.

This isn't your average roadway—it's actually a National Park and a transportation pioneer.

The final resting place of two (or three) presidents, one vampire, and 18,000 Confederate soldiers.

A small Richmond island dotted with the remnants of hundreds of years of history.

Soldiers were buried next to Lee's house in the center of Arlington Cemetery to dissuade the general from reclaiming his property after the war.

America's first federal monument.

A monument marks the location of the first successful steamboat demonstration.

An indoor miniature village and labor of love for Laurence Geiringer, a model railroad enthusiast.

America's most famous museum of medical oddities is home to the remains of Albert Einstein's brain.

Mysterious rocks that ring musically when struck.