不戦条約
Charles Lindbergh does a solo crossing of the Atlantic. And the automotive industry begins to take off. The automobile industry booms. By the end of the decade, the Kellogg–Briand Pact is passed, which outlaws war as an instrument of national policy. Herbert Hoover follows Coolidge as president, and the prosperity of the nation is shattered by the stock market crash of 1929, which begins the Great Depression.