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

The extensive relics of an ancient Roman and Phoenician fish processing plant hide in a town park.

Small plaque marks the spot, but the true center is located about half a mile away on a private pig farm.

An architect transformed this abandoned cement factory into his castle-like workshop.

Small French town or alien garage?

The site of the first medieval crusade that pitted Christians against Christians.

Rare karst landscape eroded from a flat seabed.

South Carolina's last remaining slavery auction house is now a museum devoted to its own tragic history.

Charleston's historic city jail once held everyone from pirates to Civil War POWs.

Paths are maintained, but trees have taken over plots.

A unique blue and yellow phone booth in America's "Little Sweden."

A landscape of massive spherical boulders are the main attraction in this Kansas State Park.

Repository for more than 22 million pickled specimens.

Eighty million natural history specimens call this gargantuan museum home.

The Metropolitan Police refurbished the blue box (perhaps not coincidentally) the same year "Doctor Who" returned to TV screens.

This too-low North Carolina railroad trestle is still a notorious big rig executioner.

The fastest mail service in the west is tracked and memorialized along this 1,400 mile trail.

The first home of the doomed aviator Amelia Earhart.

This quaint museum lets you take a ride on its antique carousels.

Step back in time on this preserved 1800s farm.

This road in the Great Smoky Mountains was supposed to assuage a displaced community, but ended up a $52 million dead end.

For two weeks every June, fireflies in the Smoky Mountains perform an astonishing light show.

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

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