The world's longest known cave system.

This research center for rare prosimians is studying how they sleep to help prolong human life.

One of the oldest used bookstores in the U.S. has been selling antiquarian treasures since 1825.

Berthed at the Charlestown Navy Yard in Boston, "Old Ironsides" is the oldest commissioned warship still afloat.

The massive machine creates cracking displays of indoor lightning.

Dedicated to one of the darkest moments in Irish history, this memorial has faced its fair share of backlash.

The American Revolution was galvanized into serious action due to the tragic clash with British soldiers that occurred at this location.

A pair of black granite tails dive into a sea of grass in landlocked Vermont.

According to the experts at the Guinness World's Record office, this is the longest candy counter in the world.

This picturesque abandoned home is rumored to be a spite house.

The world's only international cryptozoology museum is host to an unrivaled collection of mysterious objects.

This 1920s Dutch barge is now a floating bookstore.

The oldest Italian café in Boston, this spot also serves as a veritable museum of vintage coffee ephemera.

Shelves covered in dozens of coffee bean varieties fill this North End institution.

Richard III supposedly disposed of his nephews' bodies here in an effort to seal his claim to the throne.

A massive sustainable farm designed by the mastermind behind Central Park.

Scary metal statues adorn some of the signature buildings of Burlington, VT.

This 38-drawer structure claims the superlative title, but it isn't the world's only giant filing cabinet.

The sweetest graveyard in the world is filled with headstones for dearly de-pinted ice cream flavors.

Known as one of the most climbed mountains in the world, this barren peak is permanently bald thanks to an anti-wolf fire.

Come for the gun-toting hillbilly madman, stay for the ice-cream loving basketball bears.

These towering spires and glowing walls are carefully crafted from hundreds of thousands of icicles.

Even Henry David Thoreau found this glacial pothole irresistible.