Jean Baptiste Point du Sable founded Chicago in the early 1700s. It was founded to create a canal to let boats on the Great Lakes to connect to the Mississippi River. Later, the city became a trading center for food, crops, and fur. The city grew very fast because of how the river back then was clean and healthy to drink. In 1837, Chicago became a city. The city grew until the Great Chicago Fire in 1871. The fire lasted for almost a week. Almost half the city and its population were lost in the fire. After the fire, Chicago grew faster than ever.