It was a mixture of various reasons, although for the Spanish and Portuguese it was a question of reaching India for spice trades after the embargo instated on them by the Ottoman Turks.
The Portuguese went around Africa, and the Spanish tried sailing west across the barren ocean, and accidentally discovered America through Columbus.
Between 1935 and 1937, Congress passed three separate neutrality laws that clamped an embargo on arms sales to belligerents, forbade American ships from entering war zones and prohibited them from being armed, and barred Americans from traveling on belligerent ships.
The fight against fascism during World War II brought to the forefront the contradictions between America's ideals of democracy and equality and its treatment of racial minorities. Throughout the war, the NAACP and other civil rights organizations worked to end discrimination in the armed forces.
After the civil war, railroads connected the country on a national scale, boosting the economy and leading to mass production, mass consumption, and encouraging entrepreneurs.
