Inner Space Cavern is a karst cave located in Georgetown, Texas. The cave was discovered by the Texas Highway Department in 1963 during the construction of Interstate 35. There were several large openings to the caverns during the Ice Age, and several skeletons of prehistoric Ice-Age animals have been found in the caverns; many were trapped in the cave after they fell through the opening, unable to escape, and others drowned in thick, quicksand-like mud at the bottom of watering holes.