An optical illusion from 2016 has resurfaced and is once again causing a stir online.

The internet is full of eye puzzles and tricky images, but this particular one has left many scratching their heads until they finally cracked it. 

Even if you try, it’s hard to pull your eyes away from what looks like just an ordinary picture.

Once the image captures your attention, you’re hooked; you have to figure out what’s hidden before you can move on.

This time, it's a seemingly innocuous photo of a brick wall.

Really, it’s just a brick wall, nothing more. Or so it seems.

Take a closer look for yourself—it’s merely a picture of a regular brick wall.

Check it out if you don't believe me:

The image originally appeared on Facebook, where the person who posted it challenged viewers to spot what was unusual about it.

The photo left many people puzzled on social media.

In the image, there’s a brick wall with noticeable erosion between the bricks, creating fairly large cracks.

It seems like there’s nothing more to it than that—just bricks, right?

But once you see what’s actually there, you can’t unsee it.

Frustration was common in the comment section.

One person wrote: "Is it the rock thingy? Is it a turtle head or something? I can't see anything else."

Almost, but not quite.

Another person said: "That brick wall illusion thing actually ruined my life."

If you haven’t noticed it yet, hold on, because we’re about to reveal the secret.

Still don’t see it? Ready to find out?

Alright, here's your chance to discover the hidden object in the photo:

There it is—a big lit cigar was cleverly hidden in the wall all along.

This puzzle isn’t the only brain-teaser that has baffled the internet over the years.

Other examples include an image of a crowd of snowmen with a hidden element.

Some optical illusions can show two different things at once.

A classic example is an image that looks like both a young woman and an old woman, depending on your perspective.

Another illusion cleverly hides the owner of a horse within the horse’s body.

There are even animated illusions, like one featuring a person with an extended foot that appears to rotate.

With a bit of focus, you can even change the direction of the rotation just by using your mind.