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

Ice cream stand, snack bar, and time capsule of milk conveyance.

Berthed at the Charlestown Navy Yard in Boston, "Old Ironsides" is the oldest commissioned warship still afloat.

The site of Paul Revere's historic two lantern warning.

The Boston square dedicated to the dark poet who was born nearby.

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

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

Tucked away in the Tower of London is the weapon once used to execute high-profile prisoners.

There's an exclusive Beefeaters pub hidden in the Tower of London.

Six ravens are kept captive (but well-fed) at the Tower of London to prevent the fall of the Crown.

Mary Kelly was last seen here before she was murdered by Jack the Ripper.

A historic London pub with prison cells in the cellar and a "spy room" on the second floor.

A labyrinth hides in plain sight at each of the city's 270 Tube stations.

London's last remaining public soapbox site has seen speeches from Karl Marx, Vladmir Lenin, and George Orwell.

Tucked in a nondescript downtown Brooklyn mall is a bar containing a remarkable turn of the century anatomical wax collection last seen in 1920s Berlin.

This elaborate towering structure was once famed for its revolutionary height.

Yo, Adrian!

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