Strange stacked stones spotted on Mars | Space photo of the day for May 21, 2026

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NASA's Mars Perseverance rover has stumbled across an unusual sight: a stack of rocks on the Martian surface.

How did they end up this way? Did Perseverance knock them over? So many questions.

What is it?

Perseverance, or Percy for short, captured this bizarre image of rocks stacked on Mars on May 13(or Sol 1859, the rover's 1,859th day on the Red Planet). The image was captured with the rover's Mastcam-Z camera — a pair of two cameras located high up on the rover's mast, looking almost like a pair of eyes that the craft sees through.

You may have seen rock stacks like this while hiking, and while there can sometimes be reason to knock them over, some serve as important trail markers, according to the National Parks Service.

But this rock stack isn't pointing the way on any hiking trail. Instead, it's sitting strangely on the surface of the Red Planet appearing as three rocks stacked on top of one another, almost like a sandwich, in the middle of the dusty, reddish terrain.

However, it's more likely that what we're seeing is actually one rock that broke apart this way due to wind erosion or being exposed to flowing water on ancient Mars. Based on observations made by NASA's other Mars rover, Curiosity, scientists suspect that winds are the primary force of geological change on Mars, wearing down rocks over hundreds of millions or even billions of years.

Why is it incredible?

This isn't the first strange rock we've seen on the surface of Mars. Everything from a sphere-studded rock to bizarre evenly-spaced rocks and even a striped rock have been found by NASA's Mars rovers, sparking curiosity along the way. Conspiracies even arose when a photo from NASA's Viking mission in 1976 revealed a rocky site that, to some, resembled a human head and face.

While it's fun to explore and entertain the "what ifs" when we stumble across something new or unusual, getting to the real answer can be even more interesting.

No humans have ever been to Mars (yet), so we can be certain a rogue hiker didn't stack these rocks up for fun. But uncovering the true backstory of these rocks and their appearance on Mars can help scientists to better understand the planet's history and inner workings.