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

Saintly bones pressed into a wax effigy of a Catholic superstar.

Noirish green neon marks the location of one of the oldest private detective agencies in France.

Skeletons, medical artifacts, and other obscure and precious treasures all displayed in a wooden pharmacist's cabinet.

An off-the-beaten-path boutique stuffed with an eclectic collection of upcycled goods.

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

A horde of stray cats rule in this secluded Parisian cemetery under a bridge.

This iconic Parisian bookstore doubles as the "Tumbleweed Hotel" for traveling writers.

This massive library holds what was once the largest book collection in the world.

This lesser-known leaning tower is all that remains of the medieval castle of Vernazzano.

Armenian monks at an island monastery in the Venetian Lagoon make a rare rose petal jam.

A dismembered holy head stares out from her beautiful reliquary at the St. Dominic Basilica.

The Sighignola summit on the Swiss border offers views so breathtaking it's been named one of the most beautiful places in Italy.

Architectural monsters are devouring this palace's every door and window.

Renaissance villa and gardens complete with a tormented colossus.

This 14th century wine cellar is home to the oldest barrel-stored wine in the world.

Designed as a labyrinth, this subterranean prison was crafted without bars or doors.

Deliberately hidden for centuries, the magnificent Saadian Tombs were eventually uncovered in 1917.

The oldest known university in the world is in Fez, Morocco.

An awe-inspiring mosque in Morocco with one of the tallest minarets in the world.

It took 40 years to build this Eden-like garden in Marrakech, later restored by Yves Saint-Laurent.

This former office building has been transformed into an immersive music venue and art space.

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

The ruins of a cotton mill that was burned in the Civil War are still hidden in a Georgia forest.