Coke bottles, ticket stubs, pre-historic debris discovered in world’s longest-known cave system
[ad_1] Archeologists on a mission to see the place a mysterious passageway below the world’s longest identified cave system goes are uncovering nineteenth and Twentieth-century artifacts within the historic dig. This collapsed sinkhole, the most important identified pure entrance to the Mammoth Cave system, is believed by researchers to be the place the cave’s in depth […]