What happens to a theme park when what it's themed after becomes almost completely forgotten? You wind up with Dogpatch USA, a once-thriving amusement park in the Ozark Mountains that has sat empty longer than it was open. When it's done, the former theme park will reopen as Marble Falls Nature Park, a 400-acre nature preserve, making this land available to the public again after decades of disuse. When Dogpatch USA opened in 1968, "Li'l Abner" had been a major part of American pop culture for over three decades. That's named after a "Li'l Abner" character.