Scattered throughout London are ancient remnants of the city's former bounding wall.

A memorial for public executions that dates back to the 14th century.

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

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

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

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

The perfectly preserved underground rooms where Churchill plotted the war against Germany.

This giant, rotating globe was built to celebrate the expansion of a company that makes steam cleaners and pressure washers.

In the parking lot of a fast food restaurant, a statue memorializing a prolific bull elephant.

A portion of the old Pirates stadium over which a defining home run once flew still stands even after the rest of the stadium was torn down.

The unique location where the former president was rapidly sworn in.

The world's first time capsule lies behind a welded steel door in Atlanta.

A fascinating aviation museum where you can chat with the veterans who once flew the aircraft on display.

Once one of the largest producers of pig iron in the world.

The metal spire on the roof of this tower was intended as an airship docking station, but it was never actually used.

This massive monument has been telling the time for 150 years—at a slight angle.

This futuristic airport terminal was abandoned for decades before reopening as a hotel—with a vintage plane of its own parked out back.

The oldest pub in Ireland may also be the oldest surviving bar in the entire world.

These engineering masterpieces are a dominant feature of the Belfast skyline.

The ship built to ferry passengers and goods to the doomed Titanic is now the last remaining White Star Line vessel.

A giant sculpture of the legendary "Salmon of Knowledge" celebrates the return of fish to Belfast's River Lagan.

While The Dick Lane Velodrome is Atlanta’s official home of track cycling and Georgia's only velodrome, many are unfamiliar with this community gem.

Two Civil War-era cemeteries stuck between runways at the world's busiest airport.

Millions of pieces of Venetian glass showcase the life of Christ.