A simple but powerful tribute to the 20 victims of the 1692 witch trials.

In 1958, an MIT fraternity pledge laid down on this bridge and instituted a new, unique unit of measurement.

This bridge was the birthplace of a unit of measurement based on a fraternity joke.

Narrowest house in Boston.

Millions of numbers carved in glass represent the tattoos forced upon victims.

Dedicated to one of the darkest moments in Irish history.

The American Revolution was galvanized into serious action due to the tragic clash with British soldiers that occurred at this location.

This statue intended for children to enjoy became a minor political spat.

Statue in Salem of the woman who starred as the witch Samantha in the sitcom "Bewitched."

The only structure left with direct ties to the Salem witchcraft trials of 1692.

The thousands of shades on display — some toxic, others impossibly rare — are a library of more than just color.

An anonymous art project beneath Longfellow Bridge where hundreds of trophies line the steel support beams.

This hidden 13th-century tavern room has a few Shakespearean connections.

A statue erected in honor of the toadish nickname given to Jersey residents by the French.

A plaque is all that remains of a lost Oxford transport hub.

On a wall in linear London, a plaque hangs at the high water mark of one of the worst floods in fictional Kcymaerxthaereal times.

Since 1887, this old-school shop has stacked its shelves with extraordinary coffees and teas.

The signs of a long buried road can still be found hidden beneath a London sewer grate.

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

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

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

The Tudor-style cottage in the middle of the square is not quite what it seems.

Graffiti from the 16th and 17th centuries cover the walls of this part of the Tower of London.

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