1. In 1931, the Star Spangled Banner became the U.S's national anthem.
2. In 1932, Nebraska's stat capitol was finished.
3. In 1930, Mahatma Gandhi's Salt March started.
4. In 1930, the dwarf planet Pluto was discovered.
5. In 1931, the Empire State Building was finished being built
6. In 1932, Amelia Earhart was the first woman to fly across the Atlantic solo.
7. In 1934, the Dust Bowl happened which like arKZo said, the weather caused severe damage to farms,
8. In 1939, World War II begins along with The Wizard of Oz which premiered in the same year.
Hoped this helped!!