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By looking at the layers beneath our feet, geologists have been able to identify and describe crucial episodes in life’s history. These key events frame the chapters in the story of life on earth and the system we use to bind all these chapters together is the Geologic Time Scale.

Thanks to Studio 252mya for their illustrations. You can find more of their work here: https://252mya.com/licensing

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Addition to image credits: some footage from this episode is from VideoBlocks.com