It took a little bit of clicking, but I found that the southern boundary of this sanctuary is a little bit north of Milwaukee. It's not very large relative to

It took a little bit of clicking, but I found that the southern boundary of this sanctuary is a little bit north of Milwaukee. It's not very large relative to the entire lake. I wondered why this specific place? What is so special about it? My best guess is that shipping to/from Milwaukee and the other Great Lakes would have passed through this particular region and there must be some some bathymetric feature [1] that causes particularly bad waves or something. Further south, Chicago was for many decades the busiest port in the US and yet has few shipwrecks: Lake Michigan is relatively shallow in that area - you probably need to go 5-10 miles offshore before the water gets more than 150 feet deep. [1] https://www.ngdc.noaa.gov/mgg/image/michiganlarge.jpg https://www.ngdc.noaa.gov/mgg/image/michiganlarge.jpg