Seeing is believing… until you see something unbelievable, like an optical illusion. By definition, optical illusions are images that differ from their impartial reality. Sometimes, the most popular illusions are those that simply require another perspective—and their secrets are actually hidden in plain sight.

Other times, no one can figure out the truth at all. Naturally, the Internet is chock-full of this sort of trickery. The following illusions may or may not have been staged, but one thing’s for sure: they’re definitely going to throw your brain for a serious loop!

1. Can you tell what’s going on in this photo of this woman sitting on a workout bench? Doesn’t it look like her feet are pointed in the complete opposite directions from her body? She must be in pain, based on the expression she’s making…

Some internet users have claimed that she has fake legs, while others said it’s simply a mirror trick. What do you think? The photo surfaced in 2015, and even after all that time, no one has found the actual answer!

2. Here’s one that was the subject of a huge debate recently. Notice anything strange about any of these women sitting in a group on the couch? Focus your attention on the third woman from the left. Where are her legs?

When this photograph first began to circulate on Reddit, hundreds of users instantly began to theorize what was going on. Perhaps this comment can help provide you with some much-needed answers…

Though helpful, it’s not quite right. Maybe this red circle will help you see that this girl’s legs are actually “wearing” the second pair of blue jeans from the left. You can see them if you look closely. The friend next to her is wearing black jeans, which are hidden.

3. Notice something strange about this bench? It almost looks like these women are sitting on air, but how are they doing that without falling down onto the ground below? They must have some strong legs!

4. Here’s a tricky one: Can you figure out what’s wrong with this image and why it’s circled? While your senses have likely trained you to be critical of photos, perhaps you’re looking too hard here. Psst… this isn’t a red circle. It’s just a hula hoop!

5. This looks like your average picture of a girl in a bedroom, but there’s something strange about her. No, it’s not her seductive expression or what she’s (barely) wearing. Just look closely and you might notice it…

Look at her fingers. How many do you see? There are five, but guess what—she’s definitely not biting down on her thumb. Since this picture first surfaced, many Internet sleuths have tried their best to figure it out. The most obvious theory is just some good photo editing.

6. Even the most well-trained optical illusionists have a difficult time with this picture. Try to spot the cell phone in this photo. It’s a toughie! Every time you think you’ve finally located it, there’s actually a good chance you’re wrong.

Here’s a hint. The dark pattern of the rug makes it nearly impossible to spot the phone with the naked eye. Even with the nifty red circle here, you probably still can’t see the cell phone clearly!

Still can’t find it? Maybe this image will help you. You see, the phone isn’t just a normal cell phone; it has a floral case that makes it blend in perfectly with the carpet. If you found this on your own, you must have magnificent vision!

7. This illusion will definitely trip you up. This might look like just a normal passenger seat you’d find in any modern vehicle, but do you notice something strange about the pattern of the lines on the leather seat?

Here you go! This iPad has a cover that’s very similar in appearance to the seat’s upholstery! The person who owns it had better be careful. If they leave it lying on the seat like that, someone is bound to sit on it!

8. This optical illusion is just downright confusing. This man finally made it all the way to the Great Wall of China, but do you notice something different? Doesn’t it look like the Great Wall has flipped on its side? How did he possibly do that?

Take a look at the people in the background! You can easily see two visitors walking upright along the path. The man in the picture is actually just doing a sideways plank while holding himself off the ground horizontally. That’s some core strength right there!

9. At first glance, the picture of this woman kneeling on a bright red sheet seems harmless, but then you’ll notice her legs. Doesn’t it look like she has three of them? Can you tell what’s really going on here?

If you look closely, you can clearly see that she is simply holding a vase near her legs. The shape and color of the vase are so close to that of her tights that it makes it appear to be a third leg!

10. Can you match this couple’s faces to their bodies? Once you realize that the blonde-haired man is actually the one sitting in the computer chair and the girl is actually standing, it’s easy to see how everything became twisted in the process.

11. People can get pretty creative with depth perception and photography. It might look like a giant man is going to make a meal out of a woman while lying in the sun, but she’s actually just standing far enough in the distance. It’s a matter of perspective!

Aren’t these illusions wild? You probably couldn’t guess that last one! These are pretty difficult if you aren’t sure what you’re looking for.

Share these optical illusions with your friends below!