Thirteen sites in Iowa are on the annual list of the most endangered historic properties in the state, a list compiled by the Iowa Historic Preservation Alliance. The list covers a variety of structures including a swimming pool, a church, a school and a campground. Joyce Barrett is the director of the non-profit group. She says citizens around the state nominate buildings, which are then chosen for the list by a panel of experts based on four criteria.Barrett says they try and help property owners preserve or restore the properties.Barrett says owners of the properties often don’t know what they want to do with the buildings. She says the alliance doesn’t try to push them into anything.She says the buildings don’t have to be restored to their original use. Barrett says about 20-percent of the buildings that have made the annual list end up being torn down. Here is this year’s list: Camp Dodge Pool in Johnston; Rotrige House in Saint Paul; Second Baptist Church in Centerville; Castle on the Hill in Sioux City; Keokuk Middle School; The Civilian Conservation Corps Camp in Moorhead; Slayton Farms Round Barn in Iowa Falls; Kyte Farmstead in Weldon; The Chicago Milwaukee Railroad Shop and Roundhouse in Sioux City; McGee one room brick schoolhouse in Manchester; Bentonsport Foot Bridge; Herriman Mansion in Wadena and the Walnut Street Baptist Church in Waterloo.