What’s the most amazing place in nature you’ve been?

That's a place I'd like to visit.

I once drove through Yellowstone in the middle of the night on the way to the Great Northwest. You've heard of the expression, " a deer caught in the headlights? " For me it was a moose. At first I mistook it for an elk. And it wasn't a bit scared as that expression implies. Conversely, it was standing in a very dominant, regal manner on a nearby ridge as if it was posing for a picture.

Omg! :o I was gonna say that!

I'd say they're pretty impressive, although not so much at night, I imagine.
https://i1.trekearth.com/photos/32901/dsc05145.jpg

The Grand Canyon is nothing at night, either.

Niagara Falls was amazing to me, too. All that power...
https://imgur.com/a/X5VYm8Y
(That's my own photo, by the way.)

Canada is the most likely foreign country I have even a chance of seeing. If you were to recommend one can't-miss Canadian site, what would you choose?

About 10 years ago, shortly after our father's funeral, my brother and his wife took me on motorcycle trip along the north shore of Superior along highway 61. We eventually turned north and went into the Boundary Waters wilderness area, along the Gunflint Trail and nearly to the Canadian border. It's a great memory of mine.

I have been to Sedona, and you're right about it being mystical, although I didn't know it had a name.