An "inside out" building in the historical center of Paris, featuring Europe’s largest modern art museum.

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

A museum of magic with a Sadist past.

High atop the Eiffel Tower is a small apartment built exclusively to entertain the science elite and make the rest of Paris jealous.

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

Abandoned railway line circling the city of Paris.

Notorious artist squat renovated into legal studios.

The macabre collection of Jacques Sirgent, an expert scholar on the undead and all of their trappings.

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

Guns that have been defending San Francisco since 1904.

Faceless white figures loom over the city from the rooftop.

The grand, column-fronted, sculpture-adorned home of the ambitious digital library.

Radioactivity still cause for concern at this urban explorer's paradise.

Russian history in San Francisco.

Appropriation-friendly collection of books, periodicals, and more.

Alleyway plaque commemorating the death of a fictional character in The Maltese Falcon, not far from the author's home.

Longtime headquarters of controversial boys' club for the world's wealthiest and most powerful.

Tenacious mummies survived dental problems, eternal entombment, and more than their fair share of devastating fires.

With the touch of a button, you can read a randomly selected short story.

This partially buried wreck is one of the most complete of its kind but is only revealed when the sea allows.

The randomness of this wall of lava lamps helps encrypt up to 10 percent of the internet.

A 300-ship graveyard, with a few still visible at low tide.

In this century-old literary safehouse, print is alive and well.

Big gun installations, built over a massive cemetery, now abandoned & hidden in trees.