Americans were suspicious of Japanese beachside it was the Japanese empire that killed so many in Pearl Harbor. They were fearful of Germans because it was Germany that was an aggressor and enemy of America during the Second World War.
Scientific theories said that dark-skinned people were less intelligent than white people and misguided theories justified the passage of laws that kept African Americans from voting.
Mass production of steel, large suspension bridges, steel frame construction in buildings. It allowed impurities to be removed cheaply and easily, enabling steel to be produced in mass quantities.
