The tradition of open-air secondhand and antiquarian bookselling in Paris dates back to the Renaissance.

A 400-year-old church covered floor to ceiling in ex-voto offerings from the faithful.

The remaining relics of the patroness of Paris lie in a chapel under a striking double spiral staircase.

With a history of slaughter, feast, and famine, remnants of the pork industry decorate this area--even its church.

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

A 16th-century fountain marks the site of a lost medieval cemetery once filled with mass graves.

A popular shrine where the Blessed Virgin allegedly appeared in 1830, displaying a holy armchair and two incorruptible remains of Lady Saints.

Remains of Roman amphitheater hidden in a sleepy quarter of Paris.

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

Twelve grave-faced marble angels guard the emperor's tomb at Les Invalides.

This former “ante-chamber to the guillotine” has been refurbished to illustrate the brutal history of French justice.

The ruins of a Duke's bucolic dream, where camels once roamed alongside "Dutch" windmills and faux-Italian vineyards.

A museum on the history of Paris, including a set of Napoleon's toiletries, Proust's room, and relics of the Revolution.

Medieval museum built over Roman baths that features famous tapestries of a lady and a unicorn.

19th century pendulum and a clock restored by a rogue group of guerilla artists.

France's national museum of scientific and industrial instruments.

A mysterious shape catches the eye in this 16th-century painting.

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

This one has sailed five times as far as Sir Francis Drake's famous ship.

Never actually a tree at all, this spot was the site of London's public hangings for nearly 600 years.

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

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

A plaque hangs near the execution place of the Scottish Independence leader famously depicted in "Braveheart."

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