Take a moment and let this one sink in.
It sure seems like the photographer turned a bit to the left before snapping the right-hand image. It’s the lines in the cobblestones — they’re all tilted in the second image compared to the first.
A second glance reveals some irregularities, though. Though the lines look tilted relative to each other, the rest of the image looks unchanged. The trucks are in the same place, we see the same patch of sky, and if you look closely, we see the same exact cobblestones in each.
These two images are totally identical.
It’s an optical illusion, and like so many of its kind, it relies on perspective to warp our minds. The culprit here seems to be those lines. Because the picture was taken at an angle, they appear to grow less angled as we move left to right. Seen in just one image, this lines up with what we would expect. Only when the opposite edges are placed next to each other does the visual phenomenon look out of place.
If you’re not convinced, check out this visualization from an Imgur user:
When the images are superimposed, we see the illusion for what it really is. The trick here seems similar to the famous cafe wall illusion, which relies on patterns and lines to make straight lines bend.