Consider this on Google Maps:
https://www.google.ca/maps/@46.5106155, ... a=!3m1!1e3
Notice the square-rectangular things. They're submerged in 10 or so feet of water, and I've been trying to work out what they are.
I know that many decades ago the city used barrage balloons to fend off aerial attack during World War I and II; could these be the anchors for them?
