This isn't an event, but a person. Mata Hari, born Margaretha Zelle, she was born in the Netherlands and moved to France at a fairly young age.
She had no money and needed a fresh start, so she created a new persona. She donned jewels, smelled of perfume, wore little clothes and danced seductively. She made her dancing debut in a salon, and she instantly became a success. To sound more exotic, she took the stage name "Mata Hari", Malayan for "Eye of the Day" (the sun).
She quickly became famous. She was invited to big parties and had a large number of lovers, mainly military men, providing financial aid for her in exchange for her company.
During WWI, her frequent traveling across international borders and her varied companions caused several countries to wonder whether she was a spy or a double-agent. The French were confident she was a spy and arrested her on February 13th, 1917. After a short trial in front of a military court, she was sentenced to death by firing squad. On October 15th, 1917, she was shot and killed. She was 41.
After her death, her stage name "Mata Hari" became synonymous with spying and espionage.