In the mid-19th century, photographs with ghostlike figures became collectible amusements thanks to the invention of the stereoscope – a device that created three-dimensional optical illusions.

Among these collections of sights unseen were plenty of ghostly images. “The Ghost in the Stereoscope ... engendered huge controversy. But in the Halloween season, it’s fun to contemplate ...

Kick off the festival of spirits, spooky vibes and so much fun with these cute and beautiful messages, greetings and more.

Among these collections of sights unseen were plenty of ghostly images. “The Ghost in the Stereoscope,” a colorized card ... and their claims to record the spirit world engendered huge controversy.