Today’s the first full day of summer, which may start some people thinking about taking a plunge. The largest swimming pool in Iowa is also one of the biggest pools in America. Located at Camp Dodge, where the Iowa National Guard is based, the pool’s manager says it’s a well-kept secret since some people mistakenly think it’s not open to the public.Bob Nuzum says the 78-year-old pool is the third largest outdoor filtered swimming pool in the U-S. It holds three-and-a-half million gallons of water. It also holds three-thousand people, as many as the entire town of Tipton.Even though the Camp Dodge Pool has already been open for a couple of weeks, Nuzum says the weather hasn’t been too cooperative for swimming, but he expects that to improve as the weather heats up.Though some pools in Iowa have had trouble finding lifeguards, Nuzum has a full staff hired already. It takes six lifeguards to keep a watch on the football field-sized pool during the peak hours.