(CBS) — A history lesson about the Flag of Chicago, which is now 100 years old.

Mayor William Hale Thompson appointed a commission to choose a flag. The winning design was adopted in 1917.

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The white sections represent the North, West and South Sides of the city.

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The top blue stripe is for Lake Michigan and the North Branch of the River. The bottom blue is for the South Branch of the River and the Chicago Sanitary and Ship Canal.

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The four red-stars represent historic events in Chicago: Fort Dearborn, The Great Fire of 1871, The World’s Columbian exposition of 1893 And the Century of Progress Exposition of 1933-34.