This mysterious artificial cave has long puzzled New Englanders.

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

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

Overgrown ruins of a turn of the century island fort that sees very few visitors.

Civil War-era Fort designed to withstand invasion and attack, with tricky traps called "murder holes."

Second largest wastewater treatment plant in the country.

Beautiful steampunk ghosts of early Massachusetts.

The remnants of a Gilded Age elegance preserved in the middle of a stark modern tower.

Around 160 years ago, this spot marked the location of a wharf along the shores of the Charles River.