The Arve and the Rhone in Geneva, Switzerland…the vastly different flow of water in each keeps them separated where they converge.
Yep. Manaus, Brazil (Amazon and?) and somewhere in Georgia (not the US one) are the other ones I can think of.
https://www.cbc.ca/news/canada/north/employee-killed-polar-bears-brevoort-island-nunavut-9.6973958 Polar bears are the one land animal who will actively hunt people for food.