Humans have walked the Earth for 190,000 years, a mere blip in Earth's 4.5-billion-year history. A lot has happened in that time. Earth formed and oxygen levels rose in the foundational years of the Precambrian. The productive Paleozoic era gave rise to hard-shelled organisms, vertebrates, amphibians, and reptiles. Dinosaurs ruled the Earth in the mighty Mesozoic. And 64 million years after dinosaurs went extinct, modern humans emerged in the Cenozoic era. The planet has seen an incredible series of changes—discover them for yourself.

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  • Picture of a sugarcane worker

    The Human Cost of Sugar Harvesting

    Sugarcane harvesters in Nicaragua are being afflicted at an alarming rate with chronic kidney disease and the toll on the community has been grief and heartbreak for those suffering from the disease and for their families. Video.

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