Yellowstone is one of the 'wonders' you just have to see if you ever visit that part of the USA. Apart from the variety of wildlife and the stunning views, it also has its own micro-climate thanks to the mountains that surround the park on three sides.
This short 4 minute video is a great story about what happened when after a 70 year absence, wolves were reintroduced to the Yellowstone National Park. The results were quite surprising.