A mysterious echo seems to defy the laws of acoustics.

This lovely little pond is named after the hundreds of soldiers' corpses that were rolled into the waters during the French-Indian War.

Two mermen, eternally spitting into each other's mouths.

A sewing machine tycoon built this miniature castle for the people and to beautify a lakeshore.

This picturesque cottage was the site of Ulysses S. Grant’s final and perhaps most important campaign.

A mural of a boy making a phone call connects a southern Maine community to a town in Iraq.

This 1,700-pound edible sculpture is way better than your average chocolate mousse.

This historic graveyard monument is dedicated to a tragic victim of witch trial hysteria.

The oldest living cultivated fruit tree in North America.

Palatial mansion estate used in films including "Flowers in the Attic" and "The Witches of Eastwick."

The macabre graffiti spectacle in a quarry in a Massachusetts forest reservation.

An unrealized dream to wirelessly electrify the entire Earth.

The second-largest (of only two in the world) large particle collider is the underdog of experimental physics.

A restored Shell gas station from 1937 that includes a tow truck, the original gas pumps, and the original office.

A monument to the winner of the 1946 Boston Marathon, Greek runner Stylianos Kyriakides.

Final resting place of the two women killed on a small island off the coast of New Hampshire.

One of the few brewers in the U.S. experimenting with hop-free beers.

A cave dug by a man directed by ghosts to find pirate treasure.

At the supposed instruction of Ben Franklin and Socrates, a Spiritualist believer intended to birth a mechanical messiah here.

A large camera obscura, constructed entirely from digitally fabricated components.

This Delaware River bridge is emblazoned with a catty slogan from a more prosperous time.

This tiny structure was built by the creator of the Brooklyn Bridge.

This colonial mansion has been home to a staggering number of American historic figures.

This strange, big-tailed beast became a Pennsylvania town's unofficial mascot.