These odd structures, now called sinkites, are turning our understanding of Earth’s layers upside down—literally. Older stuff gets buried first, newer stuff piles on top—it’s like building a massive, slow-motion layer cake. These sinkites—some stretching more than a kilometer across—are actually made of younger, heavier sand that somehow ended up underneath older, lighter layers. The older, lighter sediment that ended up floating above? But the way they formed—younger, heavier sand sinking beneath older, lighter sediment—has some serious real-world consequences.