The Boxer Rebellion breaks out in China. Nationalists attack foreign diplomats and missionaries, hoping to expel foreign influences from China. The U.S., Japan, and European nations send military forces to put down the uprising.

The first auto show is held in Madison Square Garden, New York City. The cars exhibited range in price from $280 to $4,000.

The International Ladies Garment Workers Union is founded.

The first Pan-African Congress convenes in London.

Eastman Kodak introduces its $1 Box Brownie camera, making photography accessible to everyone.

Austrian psychiatrist Sigmund Freud publishes The Interpretation of Dreams. Freud invented psychoanalysis and argues that many human psychological problems are sexual in nature.

King Humbert I of Italy is assassinated by an anarchist.

President William McKinley signs the Gold Standard Act, requiring all paper money to be backed by gold, an important move in the international monetary system.

The first photocopying machine is invented in France.

A New Haven, Connecticut, restaurant serves a beef patty on two slices of toast, inventing the hamburger, although it would be another 55 years before Ray Kroc starts his McDonald's empire.

The German physicist Max Planck formulates an energy theory postulating the existence of quanta. His research lays the groundwork for quantum theory and ushers in modern theoretical physics.

The Paris Metro opens with art nouveau entrances designed by Hector Guimard.

Carry Nation embarks on a women's temperance crusade across Kansas. She and her group smash saloons with hatchets while singing.

Spectator sports take center court, as the first Davis Cup tennis tournament is held, organized by Harvard University student Dwight Davis.

Russia annexes Manchuria.

In the process of urbanization, one out of five Americans lives in an urban center of 100,000 or more residents.

1.5 million telephones are in use in the United States, 24 years after their invention by Alexander Graham Bell.