WGN Radio’s Andy Masur dives into the history of the Chicago Water Cribs. If you’ve looked out on Lake Michigan and wondered about those stone structures that stick out, they’re the Chicago Water Cribs. The structures protect intake vents 200 feet under the lake. The first was built in 1865 and up until 1990 teams of “crib tenders” actually lived in them, in week-long shifts to keep an eye on things. Two of the water cribs are still active, but now they’re automated.