A Short History of Nearly Everything by Bill Bryson

If we were to compress Earth’s 4.6 billion years of history into one single, ordinary day, the first primitive signs of life would emerge at about four o’clock in the morning. Single-celled organisms appeared early but it was not until half past eight that large quantities of microbes started to grow. The first batch of sea plants would come into being soon after, and twenty minutes later, the first ever school of jellyfish would be born. At about 9:04 at night, the ancient trilobites and other creatures arrived , triggering what is known among biologists as the Cambrian explosion, a great outburst of life in the Cambrian Period.

Close to ten at night, the Earth saw its very first signs of vegetation and its first batch of terrestrial animals. At 10:24, the great forests of the Carboniferous Period started covering the entire surface of the Earth, and the first winged insects began dancing in the air.

The dinosaurs came just past eleven at night, and later dominated the Earth. Then, they would suddenly vanish in twenty-one minutes, and the era of the mammals would begin. Humans would not enter the scene until just one minute and seventeen seconds to midnight, and all of the documented history of mankind would in fact only span a few seconds long in this countdown.