Reach 1.000 of population.
Reach 10.000 of population.
Reach 5.000 of population.
Build the Mayor's House.
Build the City Hall.
Build a Statue.
Reach 50.000 of population.
Reach 100.000 of population.
Reach 524.288 or more of population.
Build a Military Base.
Build a Space Terminal.
Build your first Arcology.