Hidden beneath the streets of London is a secret subway that only carried mail.

The bones of two medieval royal lions were discovered at the historic fortress.

Eighty million natural history specimens call this gargantuan museum home.

The handiwork of a underdog clockmaker who solved an impossible problem for an Empire, and forever revolutionized seafaring.

An inverted staircase above the entrance to the Bethnal Green Underground Station functions as a memorial for people who lost their lives during the worst civilian disaster in the U.K. during World War II.

Thanks to modern navigational tools we now know that the true prime meridian runs through a park next door.

A forgotten underground railway once whooshed trams beneath London.

A tongue-in-cheek arcade where the games are based on everyday life.

An eccentric 18th century naval officer built a ship's quarterdeck on his roof, the inspiration for Mary Poppins's "Admiral Boom."

An agreement meant to honor the Duke of Buckingham led to this unusually-named passageway near Charing Cross.

Soon after its unveiling, this giant inverted globe sparked controversy and was vandalized.

A jumble of concrete on the corner of one of London’s terraced buildings is actually a work of art.

This mosaic dedicated to John Lennon was tended for years by a Beatles super-fan.

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

The colonial home of Paul Revere during the American Revolution.

Tragedy on Little Brewster Island memorialized.

The first bell ever cast in Boston was cast by Paul Revere...and sounded terrible.

Stolen goods adorn the organ at Old North Church.

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

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

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

Dedicated to one of the darkest moments in Irish history.

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.