Not a secret, but there ARE gold and diamonds to be found in Indiana. One secret I would love to know is what caused the MASS decline of Indians in Indiana about 3,000-4,000 years ago. They were EVERYWHERE in Indiana, and then most dissappeared. Was it war, plague, drought, or ?
When WWII was coming to a close the U.S. canceled and order for some P-47 Thunderbolts. That basically shut down the Republic plant in Evansville and some say 3 or 4 finished planes, which were part of the canceled order, were towed out into the hinterlands and buried.