Under a glass sidewalk lie the remains of some of Manhattan's oldest buildings.

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

Dedicated to one of the darkest moments in Irish history, this memorial has faced its fair share of backlash.

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

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

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

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

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

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

A memorial in the Tiergarten is a reminder of the suffering inflicted on homosexuals by the Nazi regime.

An imperial church bombed to ruins during WWII now stands as a jagged memorial.

Macabre headstones carved with winged skulls, dancing skeletons, and pithy reminders of impending death.

Vienna's giant wonder wheel had a starring role in one of the greatest noir movies of all time.

On the Spree bank, discover one of the last reminders of a symbolic wall that divided, and was torn down by the people.

A fascinating insight into daily life in the Eastern Bloc.

A 98-room castle in the middle of Toronto that bankrupted a 19th century electricity multimillionaire.

Thomas Edison's home and final resting place also boasts an impressive garage, where some of the earliest electric cars are on display.

Take a step into the workshop where Edison and his employees revolutionized the world.

Infamous marsh filled with toxic waste, World War II-era London rubble, and dead mobsters galore.

This Delaware River bridge is emblazoned with a catty slogan from a more prosperous time.

On the Hudson resides one of the largest clocks in the world.

One of New Jersey's oldest surviving buildings still bears the mark of our former British overlords.

Seven people are buried in the middle of what's now a movie theater parking lot.

A giant light 13 feet high shines near Thomas Edison's old Menlo Park lab.