An old trolley bridge was converted into a breathtaking garden bursting with colorful flowers.

A 19th century library favored by Edgar Allan Poe and H.P. Lovecraft, known by locals as "the Ath."

True to its name, this bouncy walkway may be the world’s smallest suspension bridge.

Unlike other abandoned asylums this empty institution welcomes visitors, just don't go in the buildings.

This miniature feudal castle was built on a whim to honor a US Navy pioneer.

This beautiful architectural gem was the first waste treatment facility in Boston.

A spooky and decrepit mental health facility is slowly being replaced with newer digs.

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

The former locus of Boston's high culture has been shuttered and buried for over 70 years.

An enormous, inside-out glass globe built in 1935.

A historic bridge with a lovely acoustic anomaly.

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

The strikingly modern structure stands out among the brick buildings speckling the Harvard Business School's campus.

This tiny, painted door at the base of a tree stump has been a fixture of the Harvard University campus for decades.

This former Masonic hall has been turned into an art project that uses even more metaphysical iconography.

This tower pays homage to a legendary Viking fort established in Massachusetts that never really existed.

This castle constructed in 1928 was crafted from drawings of Lismore Castle in Ireland.

An alley way dedicated to graffiti and street art is a constantly changing street gallery.

Ralph Waldo Emerson spent two years living here decades before it became a Frederick Law Olmsted-designed park.

Radical Bookstore and Community Space.

This upscale streetwear store is hidden behind a fake Snapple machine in the back of a deli.

Two thousand artifacts from around the world collected by one woman who loved to travel.

From economic backbone of a community to deadly diving hole, these former stone quarries are now a park for rock climbers and graffiti artists.

This small shop walked so America could run on Dunkin'.