Soldiers train at the American University Experiment Station during World War I. The American University Experiment Station was closed after World War I and its historic boundaries are included within the Spring Valley Formerly Used Defense Site where the U.S. Army Corps of Engineers carried out cleanup efforts to remove potential hazards stemming from past military activity. Wilson Walters, a Huntsville Center employee who was instrumental in the beginning stages of the Spring Valley project, will retire at the end of this month. (Courtesy Photo)