At times, it was chaotic because it was so much land to control that the ruler split it into "states", and gave each one to a family member. But, after a while they realized some of the family had more land than others, so they began to fight. The bigger lands conquered the others with their stronger army.
Brown v. Board of Education was a landmark case in which it was finally proven that segregation in institutions of education was highly unconstitutional, so you could say that that is the greatest effect since it made other schools become open for everyone as well.
Lighting kerosene lamps. Petroleum in the form of tar from oil seeps in the ground were used to seal boats and the roofs of houses.
