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

A statue of the legendary Celtic warrior queen who fought the Roman invaders stands in one of the cities she once destroyed.

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

Exquisite wall sculptures carved in secret by an early quarryman in an obscure corner of the Paris Catacombs.

135 bronze medallions mark a French meridian line which once rivaled the hotshot Greenwich timeline.

This life-size replica of the Statue of Liberty's flame is also a tribute to Princess Diana by default.

Natural history museum celebrating biodiversity with a parade of taxidermy animals.

This bridge was constructed from the rubble of the infamous Bastille.

This demon atop the Notre-Dame de Paris looks utterly bored.

The water-powered carriages are long gone, but for over a century this funicular railway has been the fastest route to the highest point in Paris.

Amsterdam's Red Light District leaves little to the imagination.

A public urinal so pretty, it was declared a national monument.

One of Amsterdam's narrowest houses is located right across the canal from its widest.

Birthplace of the "Cat in the Cradle" and a cluster of iconic, original windmills that let the Dutch tame the seas.

A memorial for a young woman and her ghost, which are claimed to have caused countless deathly shipwrecks.

This fountain of a little boy that spits on passersby at erratic intervals is a town icon.

Thousand-year-old Viking runes adorn an ancient Greek lion at the entrance to the Venetian Arsenal.

Where Venice's gondolas go for a tune-up.

Those who own or stay at this 500-year-old, allegedly cursed house often meet terrible fates.

The pile of books behind the dignified writer gave the statue a most undignified nickname.

This palatial spiral staircase was so unusual the name "snail" was given to the noble family who built it.

This Roman statue is missing a limb from when the Venetians stole it from Constantinople during the Crusades.

Two stone columns flank the grand Venice square, but there were supposed to be three.

Renaissance hospital featuring a rotating door into which unwanted babies were dropped.