These official units of measurement—including chains and perches—lie hidden beneath tourists' feet in a popular London hub.

The mummified heart of a saint lives on in this church—after a brief hiatus when it was stolen.

Experience what life was like in Ireland during the Viking and medieval ages.

This luxury shopping lane has been protected by its own tiny police force for over a century.

The broken skateboards that became a poignant memorial to a murdered skater.

A closed London rail station created to cart away the dead still bears the marks of attempts to make it less morbid.

A hands-off space for graffiti artists to hone and display their skills.

This ornate Victorian marketplace was the setting for Diagon Alley and the Leaky Cauldron in the Harry Potter films.

One of the few remaining casualties of the London Blitz, this destroyed church has become an enchanting public garden.

The gorgeous library at Trinity College is home to remarkable treasures of Irish identity.

This picturesque horseshoe weir was first built in the 1600s to prevent flooding in the town of Bath.

A huge, bustling local market in Panama City.

In Northeastern Iceland lies something of an oxymoron: a steaming desert.

This wild explosion of color on a disused water tower tells the whimsical tale of a curious puffin.

A winding, blood-red tunnel of hardened lava navigable by foot.

This tiny museum's sizable collection is jammed into a former underground public toilet.

The collection is housed in an exquisite mansion that makes you feel like you've been transported to an Italian villa.

The fifth tallest statue in the United States is a shirtless monument to the oil worker.

This abandoned, windowless concrete block is one of the strangest buildings in Tulsa.

One of the best examples of Art Deco architecture in the United States.

A half-size replica of the World Trade Center towers above Tulsa.

An acoustic anomaly with a mysterious cause.

The rusted remains of a victim of Hurricane Ike.

The largest portal tomb in Europe has a capstone weighing around 150 tons.