Optical illusions can range from funny to downright disturbing, just like the following selection.
We may think snaps have been retouched, but often it's just pressing the shutter at the right time from the right angle. Whatever the case, they make us do a double-take and question our sanity.
Here are 16 photos that may take you a while to figure out.
1. Just a cat walking on the wall
2. Ever seen a hovering T-shirt?
3. Did you know that the sun has a lampshade?
4. He caught a fish but lost his legs
5. Need help? Turn your phone 90° to the left!
6. Emerging from the fog
7. Imagine the panic when they first saw this
8. One very long cat
9. Cerberus being cute
10. This giant was spotted in 1976
11. A man-dog and his buddy relax on the couch
12. It's easy to walk on air
13. This is how swans are born
14. Their grandma's bathroom. Gulp!
15. A rare chicken-frog
16. Clue: these 'pebbles' are edible!