Was the Niagra Falls scene filmed on location?

It looked to me like a 'blue screen" special effect.The actors were on a set and the Falls were edited into the background.

To me it appeared to be rear projection, not of the actual falls in winter, but of a model. Note the large amount of clear water and its texture on the right especially. Good effect nonetheless.

That was a process shot (rear projection). A damned good one, too!

I was wondering the same thing. It was really well done.