Iowa is an intriguing blend of bucolic farms and metropolitan cities. As the heartland of U.S. agriculture, Iowa produces hogs, cattle, soybeans, and corn. However, manufacturing has grown into a major industry in Iowa as well, and the state produces everything from microwave ovens to ethanol. Every four years, Iowa rises to prominence in the national spotlight as its voters gather for the Iowa Presidential Caucus. Since 1972, this event has been seen as the "starting gun" for the presidential race, and candidates expend enormous resources to reach Iowa's voters.