This image might look like an Oculus Rift screenshot, but it dates back to the mid-19th century. It's an example of stereoscopic photography, the 3D imaging craze of the Victorian era.
On a basic level, the somewhat forgotten art form works in the same way as today's stereo 3D; two images of the same scene are taken from ever-so-slightly different angles but, viewed together, the brain sees them as one image with an illusion of depth.
These photographs were known as stereographs, and the Tate Britain museum in London has a new exhibition of pioneering works in the genre from the 1850s and 1860s. The show's title, "'Poor Man's Picture Gallery': Victorian Art and Stereoscopic Photography," refers to the types of images that were popular at the time: Photographers would stage scenes from famous paintings using real people and hand-colour them, to bring a version of fine art to the masses.
The images would be viewed through an instrument called a stereoscope, which has two lenses to focus the separate images in a way that appears to push them toward each other and effectively blend them into one. You might have experienced the same effect when viewing slides through a View-Master, which is just a more modern version of the stereoscope.
The Tate explains that though the images circulates in tens of thousands, they're quite rare now as they were considered disposable. Those in the exhibition come from the collection of astronomer Brian May, who you're probably more likely to know as the guitarist from Queen.
It might have been considered a "poor man's" alternative to actually visiting a gallery, but stereoscopic photography is a reminder that seeing things in 3D was aspired to long before stereoscopic TV displays and virtual reality headsets made it a modern buzzword—and that the technology, at base, hasn't changed all that much since.