It's not what I thought ... and not what you might think ...
I have never spend a second thought on this until today.
I even talked about this at Steemfest, since I have the xxx in my username.
I knew, it wasn't for the red light district.
I had always just assumed, those were windmills and was going to post just that:
Turns out: They are not.
https://en.wikipedia.org/wiki/Coat_of_arms_of_Amsterdam
I'm glad, I've checked.