The first American department store, and home to the largest operating musical instrument in the world.

This charming colonial alleyway is one of the oldest continuously used residential streets in the U.S.

Dr Barnes' $25 billion private collection of art and arboretum.

Philadelphia boasts one of the best — and most often overlooked — traditional Japanese gardens in North America.

A layered tribute to the work of mosaicist Isaiah Zagar.

The world’s first penitentiary, meant to be humane, drove men insane.

America's most famous museum of medical oddities is home to the remains of Albert Einstein's brain.

The watery entrance for condemned prisoners heading to the Tower of London is still visible along the Thames.

Richard III supposedly disposed of his nephews' bodies here in an effort to seal his claim to the throne.

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

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

Hear the quietest sound from across the dome.

This London pub hides a peculiar secret: a recreation of the rooms shared at 221b Baker Street by Sherlock Holmes and Dr. Watson.

An unusual round church in London with a Templar past.

The popularity of Sherlock Holmes led to the creation of his fictional address, turning the orderly London street numbers askew.

A 300-year-old tea shop that brought tea to the English people, not to mention the Queen herself.

An interesting decoration on this historic site, this weathervane comes with as many legends as it does questions.

A former waterfront market is now in the center of town due to some interesting Boston engineering.

This monument on Breed's Hill proves that one of the most famous battles of the Revolutionary War is misnamed.

An easy-to-miss garden in Boston's North End honors the mother of JFK and others who lost children in WWII.

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

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

This landmark cemetery in Boston was created more than 300 years ago.

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