Carboniferous

The Carboniferous Period, spanning from 359 to 299 million years ago, is famous for its vast, swampy forests that transformed the planet. Named after its rich carbon deposits, the dead vegetation from these massive jungles did not fully decay, eventually turning into the extensive coal beds mined by humans today. The proliferation of these dense forests pumped immense amounts of oxygen into the atmosphere, pushing levels to historic highs. This oxygen-rich air allowed land-dwelling arthropods to grow to monstrous sizes, including eagle-sized dragonflies and giant scorpions. The Carboniferous also witnessed the rapid diversification of early amphibians and a monumental evolutionary breakthrough: the appearance of the first reptiles. These creatures developed amniotic eggs, allowing them to breed on dry land and break their dependency on water, forever altering the future of terrestrial life on Earth.