The passageways are cut into a big field north of Des Moines, and we had a great time there one Sunday afternoon, wandering through miles of maize. Iowa, the state may seem like nothing but a maze of cornfields. There certainly are a lot of farms and corn, but there's much more. In fact, there's enough to see and do in Iowa that tourism is now the third largest industry in the state. A mixture of enjoyable attractions: historic sites, including Native American burial grounds, frontier outposts and 19th-century towns; museums, including traditional but impressive sites like the Des Moines Arts Center and one-of-a-kind collections that focus on everything from the lives of Norwegian immigrants to farm toys; and nostalgic journeys, whether by riverboat, train or country road.