The Robert R. McCormick Bear Habitat plays host to a variety of species—from the lumpy Andean bears to the curious spectacled bears to the playful polar bears. Naturalistic habitats house the smaller species, complete with trees, climbing structures and waterfalls. The pair of polar bears at the north end of "Bearline" romp through one of the largest polar-bear exhibits in the world, complete with a 266,000-gallon pool and underwater viewing windows at which visitors can get nose to nose with these mighty creatures.

FIELD NOTE How do you train a polar bear? Carefully, and with a large bucket of fish.