Science Art: Ammonit-internal-xx_hg, by Hannes Grobe.

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A partially polished ammonite fossil.

At one point in history, these guys ruled the world. A few million years ago, there were bajillions of varieties of nearly every size and shape imaginable… as long as what you’re imagining has a spiral in the middle. Although they look a lot like the chambered nautilus, their closest living relative is the cuttlefish.

Medieval Europeans called ammonoid fossils “snakestones,” and believed they were proof of the snake-exterminating miracles of Saint Patrick and Saint Hilda. In India, the swirling stones were seen as traces of the god Vishnu.

Something about spirals in the middle, I think.

Image by Wikimedia Commons contributor Hannes Grobe.