Though it started as a 300 person settlement in 1832, Chicago's location near the Great Lakes and its access to the Mississippi River turned it into a major trading city overnight. The city became even more important when railroads were constructed to connect the country, making it the first major city in the "West" during the mid-19th century. By 1871, the original 300 person settlement was now home to about 300,000 people, and Chicago had become the first major city built by Americans rather than European colonial powers. Thus, it had taken less than 40 years for the new settlement of 300 to become a city of nearly 300,000, but it only took two days in 1871 for much of it to be destroyed. On the night of October 8, 1871, a blaze in the southwestern section of Chicago began to burn out of control. The popular legend is that a cow in Mrs. Catherine O'Leary's barn had kicked over a lantern and started a fire.
The story blaming the cow was a colorful fabrication, but the fire itself was very real, lasting almost two whole days and devouring several square miles of the city. The fire was so powerful that firefighters could not put it out, due to dry conditions, stiff winds, and the fact the city was mostly made of wood. Walking around Chicago today, it's easy to forget about its past as a rural frontier. That's due in no small part to the way Chicago responded to the Great Fire of 1871. Immediately after the fire, Chicago encouraged inhabitants and architects to build over the ruins, spurring creative architecture with elaborate designs. Architects descended upon the city for the opportunity to rebuild the area, and over the next few decades they had rebuilt Chicago with the country's most modern architecture and monuments. Chicago recovered well enough within 20 years to win the right to host the World's Fair in 1893.