May 6 marks the start of National Nurses Week, which spotlights the vital work of nurses. The celebration ends on May 12—the birthday of Florence Nightingale, who is considered the founder of modern nursing.

Nightingale changed medicine forever after traveling to Turkey in 1854 to tend to British soldiers injured in the Crimean War. There she discovered extremely unsanitary conditions and worked tirelessly to improve patients’ quality of care.

Back in England, Nightingale used statistics, or data analysis, to show that dirty, crowded hospitals led to many preventable deaths. She worked to promote hygiene standards that stopped the spread of disease and established a school to train nurses. Nightingale’s contributions to the field of nursing continue to save lives today.