Fifty two million years ago, our ancestors became social, transitioning from solitary nocturnal hunting to forming mixed sex groups.

[See] [How Humans Became Social] "Researchers have long believed that it was a gradual process, evolving from couples to clans to larger communities. A new analysis, however, indicates that primate societies expanded in a burst, most likely because there was safety in numbers."

[Study reveals clues to how humans became sociable] "Once the transition from individual to group living took place -- 52 million years ago in the ancestral line that gave rise to humans, and later in another branch of the primate family tree -- no shift back to solitary behaviour ever occurred. Primate ancestors that subsequently began living in pairs did not switch back to group living, whereas those that began living in harems could transition back and forth with large groups. There was never a transition directly from pair to harem living or vice versa."

Fo million years ago, our ancestors rose up onto their hind legs.

[See] [Walking Upright] "Mostly bipedal -- By 4 million years ago -- Fossils from around this time period come from early human species that lived near open areas and dense woods. Their bodies had evolved in ways that enabled them to walk upright most of the time, but still climb trees. As a result, they could take advantage of both habitats."

Oo million years ago, some of them left Africa, migrating toward Asia.

[See] [The first migrations out of Africa] "About 2 million years ago, the first of our ancestors moved northwards from their homelands and out of Africa."

Wo million years ago, some of those turned left and migrated into Northern Europe.

[See] [When did the first humans reach northern Europe?] "The coastal cliffs of East Anglia have revealed the earliest evidence of humans in northern Europe around 900,000 years ago."

Half a million years ago, now with much larger brains and much longer childhoods, roles within groups emerged.

[See] [Social Life] "More time to grow -- Beginning 500,000–160,000 years ago -- By this time, early humans had evolved much larger brains. Infants were born with small brains, enabling the head to pass through the birth canal. The brain continued to grow throughout a long childhood. During adolescence, youngsters continued to prepare for the challenges of adulthood." "Two Roads to Adulthood -- Humans are unique among primates in having long, distinct periods of childhood and adolescence. These stages enable us to learn, play, socialize, and absorb important experiences prior to adulthood. During childhood, human children depend on adults for food and care. During adolescence, a growth spurt occurs, and male and female body features develop."

Assuming an average age of 21 for a mother giving birth, you are the end product of 25,000 successive families successfully solving the problem of life, which is to reproduce.