These "mermaids" that surround a plaza in Segovia are rather sphinx-like.

A haunting collection of the vanished and disappearing natural world.

The curious underground history of keeping Paris clean.

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

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

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

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

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

The spiral staircase hidden inside this giant Parisian column was likely built for Catherine de Medici's astrologer.

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

This 18th-century sundial was designed to calculate the date of Easter each year.

This Parisian gem is one of the most incredible ethnographic museums in the world.

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

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

A mud statue stands in the dark tunnels, seeming to hold up the weight of the city above.

Once a 19th-century brasserie, this McDonald's exterior celebrates Alsatian design and the "King of Beer."

In this Parisian garden's grotesque former life as a zoo it fed exotic animals to the bourgeois and put humans on exhibit.

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

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

Indents in the pavement are all that remain from a grisly death machine in Paris.

A museum dedicated to one of Paris’s most famous residents, tucked into a corner of one of the city’s most famous squares.

This historic hotel preserves many treasures from its heyday hosting passengers on the Orient Express.

A gorgeous, Gaudí-esque stairway constructed in the city of Istanbul by a prominent Jewish family.

A fountain standing as a testament to a doomed alliance.