About a billion years ago, Earth started to come into its own. It was past the awkwardness of its younger years full of growing pains and turmoil: comet strikes and slimy water, including the Great Oxidation Event that flipped the world upside down. Roughly a billion years ago, the planet began to advance and mature, with plant life developing about 700 million years ago, but still with the occasional wild climate parties to keep things interesting.