The Great Chicago Fire occurred from October 8 to October 10, 1871, devastating much of the city of Chicago. The fire started in a barn owned by the O'Leary family and quickly spread due to strong winds and wooden buildings. It destroyed approximately 3.3 square miles of the city, leaving over 100,000 residents homeless. The fire resulted in significant loss of life, with estimates of around 300 fatalities. In its aftermath, the city rebuilt with improved fire safety regulations and more durable construction materials. The event is a pivotal moment in Chicago history, leading to its transformation into a modern metropolis.