I haven't been to Niagara Falls in many years, and it was late summer/early fall when I was there, but it sounds like it would be really incredible in the winter too. Also fewer crowds which is always a good thing :)

Next time I'm in Edinburgh I'll need to go to the falls at the Water of Leith! It was on my list of places to go when I visited but there was so much to see and do that I didn't get to it all. Your photo of it is absolutely beautiful.