They developed systems of moving water and sewage
To destroy Japan's power to make war
rapid industrialization and population growth have caused significant air pollution
They were both below the Kings and Knobles but the Knights were treated with more respect than peasants.
Answer:In October 1962, the Soviet provision of ballistic missiles to Cuba led to the most dangerous Cold War confrontation between the United States and the Soviet Union and brought the world to the brink of nuclear war