© Getty Images

Depth perception -

This picture challenges your perception of depth. Is the tall individual genuinely balancing a shorter person in their hand? No. The "small" figure is simply standing further back from the foreground. This is the basis of many optical illusions. 

© iStock

'Day and Night' (1938) -

M. C. Escher, a well-known graphic artist, is renowned for his art that portrays optical illusions. In the artwork titled 'Day and Night,' viewers have the option to perceive either a group of white birds soaring towards the east or a group of black birds heading west, based on the positioning of the foreground.

© iStock

What can you see? -

What do you perceive in this image? It could be a tree or the outlines of two faces, depending on your concentration on either a black or white backdrop.

© iStock

Ladies or columns? -

By directing your attention to the white, you'll notice three stone columns against a black backdrop. However, shifting your gaze to the black patterns will reveal the presence of two female figures facing each other.

© Shutterstock

Unsolvable box -

The impossible cube, another mind-bending creation by Escher, may first appear as a perspective drawing. However, closer inspection reveals multiple impossible features.

© iStock

Penrose stairs -

This impossible staircase, created by British psychiatrist and mathematician Lionel Penrose, features 90-degree turns that form an endless loop both ascending and descending.

© iStock

Impossible tribar -

The impossible tribar was initially conceived by Swedish graphic artist Oscar Reutersvärd, serving as a remarkable illustration of an impossible object.

© iStock

Two or three? -

The Devil's Tuning Fork is an illusion created by D.H. Schuster in 1964. While it seems to have three prongs when observed from the end, a top view reveals only two. 

© Shutterstock

Moving snakes -

The Rotating Snakes illusion, created by psychology professor Akiyoshi Kitaoka, is a fascinating optical phenomenon. Despite the image being fixed, the banded "snakes" create an illusion of circular motion.

© iStock

Ilusory motion -

This image, though it looks like it's moving, is actually completely still. It is called illusory motion, a type of optical illusion.

© iStock

Ilusory motion -

The motion occurs due to the arrangement of shapes and different colors, as reported by Mother Nature Network.

© iStock

Motionless -

Another "moving" image that is actually completely motionless.

© iStock

Optical illusion -

Scientists are uncertain to find out why the brain perceives a stationary object as if it were in motion or spinning, although multiple theories exist to explain this phenomenon.

© iStock

Optical movement -

The BBC reports that our brain can be deceived into perceiving movement that isn't actually happening due to the overwhelming information received by our retina.

© iStock

Moving around -

However, when you direct your gaze to a specific point in the picture, the motion or rotation in that area ceases.

© Shutterstock

Black or white? -

If you notice small black dots inside a white circle, don't worry. This illusion is a variation of the Hermann grid.

© iStock

Circles -

Examine closely. Does the blue circle on the right appear larger than the one on the left? Interestingly, they are both actually the same size! The circle on the left is encompassed by larger circles, leading us to assume it is smaller in comparison to the circle on the right, surrounded by smaller circles. Thus, it creates the illusion of being larger.

© Shutterstock

Visual illusion explanation -

According to New World Encyclopedia, although it may seem that the top line is longer, both lines are actually the same length. This perception may be due to our brain interpreting the arrowheads as corners, an indicator we usually use to gauge depth and distance.

© Shutterstock

Up or down? -

In this optical illusion, the dividing lines between the squares may seem distorted and uneven, yet they are actually running parallel to each other. The brain's neurons react to the contrasting colors in the image, causing the retina to dull certain areas of the lines, giving the illusion of slanting.

© Shutterstock

Zöllner illusion -

Similarly, the optical illusion showcases lines that seem misaligned, yet they are actually perfectly parallel to each other. A possible explanation for this phenomenon suggests that the brain tends to overemphasize acute angles and underestimate obtuse angles. Consequently, the eye perceives the lines as diverging in separate directions.

© Shutterstock

Real curve? -

The brain is confused by this geometrical optical illusion, as the red lines seem to curve outward while the blue lines curve inward. However, all the lines are actually straight and perfectly parallel to each other.

© Shutterstock

Fraser spiral illusion -

This example may seem like a never-ending descent in an infinite spiral. However, it is actually just a sequence of concentric circles. As explained by Illusion Works, this illusion occurs due to the orientation-sensitive simple cells and image processing happening in the retina.

© Shutterstock

Shadow illusion check -

MIT professor Edward H. Adelson devised an optical illusion featuring two boxes marked with an 'x,' appearing to exhibit contrasting shades when, in fact, their colors are identical. Our brain employs relative color and shading to identify the color of objects surrounding us.

© Shutterstock

Optical illusion -

If you come across a triangle, your eyes are once again deceiving you. This phenomenon is referred to as the "phantom edge" and is commonly known as the "T-effect" among neuropsychologists. According to the New World Encyclopedia, our neural cells perceive interruptions between shapes and mistakenly assume the presence of an imaginary line that forms a non-existent shape.

© Shutterstock

Ames room -

This optical illusion is a variation that distorts the sizes of individuals due to the irregular shape of the room. The room's floor and ceiling are inclined, and one corner of the room appears closer to the viewer compared to the other. As a result, one person appears gigantic while another seems miniature in comparison.

© Reuters

Horsetail Falls, USA -

Certain optical illusions can be observed in nature. This specific phenomenon takes place during the month of February at Horsetail Falls, situated in California's Yosemite National Park. During the precise moments when the setting sun hits the waterfall, it creates an illusion of flowing lava instead of water, giving the impression of a cascading stream of molten rock along the cliff's edge.

© Reuters

Atlas moth -

What do you see in this picture? A butterfly or multiple snakes? Surprisingly, this is an Atlas moth, as reported by The Telegraph. It uses the snake-like patterns on its wings to frighten away predators. To enhance the disguise, the moth even mimics the behavior of a snake by falling to the ground and shriveling up.

© Shutterstock

The right moment -

This photograph captured the French player Mathieu Valbuena at exactly the right (or wrong) moment and angle to make him appear half his normal height. Valbuena was actually leaning back while reaching for the ball, leading to this bizarre optical illusion.

© Reuters

Invisible man -

Chinese artist Liu Bolin uses paint to blend himself into a comic book stand in this creative image. Through brilliant camouflage, he appears to vanish seamlessly into his surroundings.

See also: Picture this: The bizarre, unseen side of the world

© Reuters