In this example, we will be using Web Map Services (WMS) in ArcGIS Pro by connecting to the Iowa Geographic Map Server (Orthoserver). WMS is a standard protocol for serving georeferenced maps over the Internet. The Orthoserver at ISU contains aerial imagery from the United States Department of Agriculture (USDA) going back to the 1930s, lidar data, USGS topographical maps, historical maps and more. We will add both historic and modern aerial imagery to a map to visually compare development changes over time near the Saylorville Dam in Johnston, Iowa.