The 28-foot granite map plots the locations of 40 theaters in New York City.

Under a playground is a little-known sealed train tunnel that likely contains the bodies of workers trapped by cave-ins.

The walls of America's oldest masonry fort famously "swallowed" cannonballs.

Erected in 1697 this Philadelphia bridge is the oldest surviving roadway bridge and perhaps the oldest stone bridge in the United States.

This Philly landmark has a giant butterfly pavilion, three floors of insect displays, and withstood a $40,000 heist.

Baltimore's classic clock tower was once topped by a rotating, 20-ton medicine bottle.

The trials and tribulations of marking Poe's grave.

The design of this historic domed church was influenced by Thomas Jefferson and intended as a statement of religious freedom.

A single light illuminates one man's overshadowed contributions to street lamp history.

An unexpected Easter egg lurks in the background of a cherub wall relief at the Breakers mansion.

A crumbling stone stable and carriage house are all that remain of a manse that was once filled with Egyptian artifacts.

This curved Manhattan building was built to house the opulence of John D. Rockefeller's oil empire.

Wall Street has a new heroine, a bronze statue of a small but fierce girl.

Built hundreds of years ago this downtown iron barrier once protected a much despised king.

This historic address is home to the beloved ball and is an almost totally empty building among the most expensive real estate in the world.

A pedestrian island in the middle of world-famous Times Square emits a strange (and purposeful) humming noise.

Metal sculpture folk art lining the Kansas Highway.

World's first "penitentiary," meant to be humane, drove men insane.

An abandoned cemetery lies in ruins as the surrounding forest swallows it whole.

The Vermont square that inspired Shirley Jackson's "The Lottery."

The building that inspired Shirley Jackson's "The Haunting of Hill House."

A bygone village occupation lives on via this quaint public chalkboard.

The oldest building in Vancouver's Chinatown is now home to one of Canada’s largest contemporary art collections.

A town wears its heart on the sleeve of a smiling girl, arms flung wide open in a cheerful greeting for all who encounter her.