Carved, egg-shaped stone with no explanation.

Trash escaped from a landfill to fill beaches with all kinds of treasure.

A former zoo turned public park, where visitors can hang out in the old animal cages.

This headstone-like marker inscribed with three words has been an utter mystery for over a century.

A mysterious stone embedded at the base of a historic Boston building.

Located in Faneuil Hall, the headquarters of the Ancient and Honorable Artillery Company of Massachusetts has stood the test of time.

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

Hidden inside one of the world's most well-visited zoos is a secret plaque promising eternal life.

A morbid secret lies hidden within the beautiful walls of the Boston Athenaeum.

No one messes with the Massachusetts sacred cod, not this time...

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

The first and only carousel with a lineup entirely of insects.

Mrs. Mallard and her brood are a beloved fixture in Boston Public Garden.

This unassuming stone commemorates a condiment factory gone up in smoke.

Museum dedicated to awful artwork.

A tiny monument to the classic American candy.

One of America's most historic homes also holds a startling literary legacy.

The ruins of one of the first railroads in the U.S. lie hidden within a neighborhood cul-de-sac.

This Boston medical museum features the skull of the famous medical case of Phineas Gage.

Located in a beautifully restored ice house, this museum is the result of decades of hard work and devotion to the craft of plumbing.

Abandoned Coast Artillery fort now serves as graffiti canvas and sightseeing vantage point.

This derelict building used to house infirm Freemasons, their widows, and orphans.

From bench to vandalism to art, this silly prank seat was funny enough to become permanent.

The oldest playground in America.