When most people think about catastrophic volcanism, their minds immediately go to places like Yellowstone. The idea of a “supervolcano” has become almost legendary in pop culture, with documentaries and headlines warning about what could happen if Yellowstone were to erupt again. And to be fair, Yellowstone is enormous. A single eruption from a system like that could blanket huge portions of North America in ash, disrupt global climate, and cause devastation on a scale humanity has never witnessed.

Ever wondered why oceanic fossils exist at the peaks of the Rocky Mountains? It sounds impossible, the idea that shells, coral, and ancient marine life now sit thousands of feet above sea level, scattered among granite ridges and alpine tundra. But those fossils aren’t misplaced; they’re storytellers. They whisper of a time when the heart of North America wasn’t mountainous at all, but submerged beneath a vast, shallow sea.

About 1.1 billion years ago, Earth’s crust tried to throw a continental-scale tantrum. Deep beneath what’s now the heartland of North America, hot mantle material surged upward with dreams of ripping the continent into pieces. Like many ambitious rift systems, it came with a plan: split the crust in three directions—classic triple junction style. One arm pointed northwest, one to the southeast, and the third dove southwest, forming a wide arc. If all had gone according to plan, we might’ve ended up with an entirely different continent—something with oceanfront property in Michigan.

To the untrained eye, an agate might just look like a pretty rock—but crack one open and it's like peeking into a geological diary. Formed in volcanic voids, agates are microcrystalline quartz that build up in rhythmic layers, each one marking a pulse of mineral-rich water over time. No two are the same, making each agate a natural work of abstract art.