The stars that we see here are NOT Stars of David but three out of the four red hexagrams that adorn the Chicago Flag. These stars stand for: Fort Dearborn
The Great Chicago Fire
The World's Columbian Exposition of 1893
The Century of Progress Exposition in 1933
Each point of each star stands for a certain meaning like: transportation, labor, commerce etc.
Picture is courtesy of kallao from Flickr.
