• The Lost Panoramas (CityFilesPress.com)
  • The Chicago River at State Street, 1902

In case you missed school that day in fourth grade when the reversal of the Chicago River was explained and, like me, are a little fuzzy on the details, here’s a cheat sheet, mostly gleaned from The Lost Panoramas: When Chicago Changed Its River and the Land Beyond, the big, historical photo book by Richard Cahan and Michael Williams, published in 2011 by CityFiles Press and the Peggy Notebaert Nature Museum.

• There used to be a “continental divide” ridge near the southwest suburb of Summit. Water on one side flowed toward the Gulf, and water on the other side ran toward the Atlantic.

• If you wanted to go from the Des Plaines to the Chicago river (or back), you had to carry or slide your canoe across this bump.