Elmo and friends are headed to the zoo -- where they have a blast recognizing sizes and spatial relationships by looking at and learning about many different animals. Big, fold-out flaps illustrate concepts like long, longer, longest, and high, higher, highest. Every colorful scene includes a fun animal fact and an activity kids can do at home. Complete with a tear-out growth chart, "Big, Bigger, Biggest" will be a hit with big and little "Sesame Street" fans alike.