By the beginning of the twentieth century, America already had a reputation for stock speculation, but the Roaring Twenties set new records.

Unusually heavy rainfall led to widespread flooding in the Mississippi Valley in 1927. The Coolidge Administration's Secretary of Everything, Herbert Hoover, was tasked with flood relief. What kind of relief you got depended heavily on your skin color.

Meanwhile, a different sort of flood was rising on the New York Stock Exchange.

Five years into his premiership, Mussolini ruled over a one-party state. He projected an image of il Duce, the tireless, indispensable leader of the Italian people as he cracked down on dissent at home and unrest in Libya.

Although Mussolini had come to power by legal means, he soon cast the moment as a Fascist revolution, and pushed for changes to the electoral system that would tighten the Fascist grip on the country.

The Algeciras Conference awarded Spain a strip of territory in northern Morocco known as the Rif, which became Spanish Morocco. But an award of territory granted by a conference of diplomats is one thing; actual control is another.

In the early 1920s, Gandhi's first nationwide satyagraha campaign saw unprecedented Hindu-Muslim unity, but led to violence and failed to achieve its aims. Gandhi spent some time in prison, but by 1930, with a Labour government in power, Gandhi and the Indian National Congress felt ready to declare independence.

Henry Ford built a successful car company based on the principle of mass production of affordable cars. But his company was eclipsed by General Motors, which had a totally different marketing strategy: planned obsolescence.

Two of the twentieth century's worst technological innovations were leaded gasoline and chlorofluorocarbons. Both were introduced by the same person, engineer Thomas Midgley.

In the 1920s, most took it for granted that Western civilization and culture was the pinnacle of human accomplishment. A 23-year-old graduate student set out to prove that this was not the case, and that even the West had something to learn from other cultures.

Charles Darwin himself noted that the development of civilization had "stopped" evolution by natural selection within our own human species. This led others to speculate on whether society could purposefully direct human evolution.