Some of the world’s most incredible animal migrations take place in the Greater Yellowstone Ecosystem. Among them are a 120-mile pronghorn migration and nine elk herds with unique migration patterns. While on assignment in Yellowstone, Joe Riis was able to capture the awe-inspiring migrations that few tourists get to see. What did you think of this incredible animal migration? Please let us know in the comment section below and remember to share the video and sign up for our free newsletter!