Hidden in the garden of physicist Erwin Schrödinger's house is a life-size figure of a cat from his famous thought experiment.

This eclectic architectural gem played witness to Zurich’s colonial past.

See the rare bloom of the "Queen of the Night" cactus at one of the world's largest succulent collections.

The most impressive of Basel's three remaining city gates.

The remains of this castle, known as the Witch’s Eye, watch over the Thur Valley.

The castle was reconstructed to fit Kaiser Wilhelm II's romanticized vision of the Middle Ages.

A charming little museum founded by the designer of the Statue of Liberty.

The oldest continuously operating mint in the world that has been making coins since the 9th-century.

The final resting place of the "father of special effects."

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

A short distance from the Eiffel Tower is the final resting place of several of the city’s more well-known and interesting characters.

This recessed garden protects thousands of mountain plants by creating its own microclimates.

A grotto-like lodge decorated with gilded mosaics, rocks and a noisy waterfall was the setting for the most sumptuous pleasure house of 1900s Europe.

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.

The history of radiation is on safe display at the foot of a radiation science laboratory.

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

Down a cobblestone alleyway is a museum dedicated to Romanticism, with a secret garden.

One of the oldest medical collections in Europe focusing on rare surgical instruments.

A museum of carnival attractions where you are invited to ride the rides.

This charming cobbled backstreet is the most Instagramable street in Paris, much to the residents' annoyance.

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

Abandoned railway line circling the city of Paris.

France's most famous cemetery, with some of its most curious tombs.

The vast, legendary catacombs hold secrets much stranger than stacked bones.