Today on Mushroom Hour we are going spelunking with the gracious Dr. Greg Brick. Dr. Brick has worked as a hydrogeologist with environmental consulting firms, at the Minnesota Department of Natural Resources, and has taught geology at local colleges and universities. He has edited the Journal of Spelean History for the past 20 years. He has published more than 200 articles about caves and was the recipient of the 2005 Cave History Award from the National Speleological Society. His has written for books including his most recent, "Minnesota Underground", co-authored with Doris Green and released in 2019. He served as co-editor of "Caves and Karst of the Upper Midwest", a textbook covering Minnesota, Wisconsin, Illinois, and Iowa. His work has been featured in National Geographic Adventure magazine as well as on the History Channel. He has led guided tours of caves for the Minnesota Historical Society and the University of Minnesota College of Continuing Education. Today he is taking us on a subterranean journey into the centuries-old caves of Mushroom Valley near St. Paul Minnesota!   TOPICS COVERED:   Caves, Karsts and Crevices   Natural Caves, Artificial Caves, Anthropogenic Caves   Exploring Caves & Claustrophobic Limitations   US Geography of Caves & Karsts   Human Cultures & Caves – Lore and Culture Around Caves    Hollow Earth Theory   The Underexplored Underground    Minnesota’s Mushroom Valley    Mole People of the NY Subway   Mushroom Farming from the Paris Catacombs to Minnesota     Economic Ecosystem that Supported Mushroom Farming in Caves   Subterranean Nightclubs - Mystic Caverns & Castle Royal    Conservation & Biodiversity in Cave Systems     LIDAR & Future of Exploring the Underworld    EPISODE RESOURCES:    Website: https://drgregbrick.com/   YouTube: https://www.youtube.com/@GregBrick   Carver's Cave: https://drgregbrick.com/carvers-cave-wakan-tipi/   David J. Weary & Daniel H. Doctor's Cave Map of the US:  https://pubs.usgs.gov/of/2014/1156/pdf/of2014-1156.pdf   Mystic Caverns & Castle Royal: https://twincitiesmusichighlights.net/venues/castle-royal/