Life, Birth
This marks the real transition of Mars into a fully independant planet, not an offshoot of Earth. At this point, around 60% of the population is native martian grown.
With an average birth rate of 5 per 100 people per year, a net migration rate that averages 4 people per 100 per year, and only around 1 death per hundred people per year, the colony has grown rapidly. The 1 million mark was reached only when including orbital infrastructure, where around 3% of the population live, along with the 2 moons, which between them have an additional 1%. The 1 millionth citizen was a girl, born at Phoenix Medical Center at around 1437 local time.