When 19th-century showman J. Quigley Dumbleton decides to open a zoo in New York City, he declares that it will be the "greatest zoo on Earth", filled with the biggest and best specimens the world can offer. And true to his word, he brings to his admirers the largest animals he can find. But predictably the animals do not fare well in their cages and begin to waste away. Panicked by his shrinking attractions, Dumbleton seeks advice from everyone -- including a young sweeper named Jeremy Pennywhistle.The boy suggests the animals need exercise and starts to take them out for walks through Manhattan where they totally disrupt Sunday traffic on Park Avenue, get tangled in Broadway's overhead wires, and create navigational havoc on the East River.The New Yorkers, of course, prefer to visit the animals in the zoo rather than have them visit the city, and so the mayor bans further strolls outside the park. But once again, Jeremy Pennywhistle solves the problem. He has Dumbleton return all the animals to their natural homes where people can pay to go and visit them. The Eco-tourism industry is born.This fun-packed story with its quirky characters and amusing illustrations delivers a powerful environmental message along with its laughs.