Enjoy a Fun Day Out in Nature! Come see us at the Sustainability Fair 2019, Saturday, August 24, 9:30 am-2:30 pm at Retzer Nature Center. Free Admission. Family friendly. Something for everyone. Hosted by Waukesha County Green Team in partnership with Waukesha County Parks and Land Use, Plowshare, Waukesha County Land Conservancy, and the Laudato Si Project.