This is one of America's truly great zoo exhibits. I've been in many underwater tunnels and I never tire of visiting aquariums with aquatic wonderlands all around visitors, but when I had polar bears and seals swimming around me on my visit to Detroit Zoo in 2008 I was amazed. Arctic Ring of Life, which opened in 2001, is the #1 reason to visit this underrated zoo.
Swimming outside this 70-foot long tunnel there are polar bears and harp seals (naturally in separate exhibits) as well as Arctic foxes in a nearby habitat. The entire 4-acre area opened to the public in 2001 but over a decade later it is still regarded by many as one of North America's best exhibit complexes.