(20 million years ago - year 99,6 (july) on the 100 year time-scale)
After some ten billion years (10,000,000,000) of Cosmic Evolution and some additional five billion (5,000,000,000) years of the Evolution of planet Earth and the Life upon it, the ever growing complexity finally led to a completely new and revolutionairy concept, just very recently, only some 20 million years (20,000,000): consciousness and self-awareness.
Consciousness and self-awareness only seems to have emerged among the most developed mamals, like elephants, dolphins, wales and some of the great apes. But it seems that only Homo Sapiens has been able to lift this powerful property to yet a higher level called "thinking", that allowed him to use and invent tools, express in languange and art, and even build societies.
The Chauvet Cave in the Ardèche Gorge in southern France, which contains perfectly preserved charcoal drawings, many of which date to 30,000 years ago. It seems that humans never really lived in it, they used it only for paintings and possibly for ceremonies.
Cave of Forgotten Dreams (2010) directed by Werner Herzog