Texas millionaire David Bamberger was so enamored with the bats he saw at the renowned Bracken Cave Preserve outside San Antonio, and was so concerned about threats to the flying mammals' natural habitat, that in the late 1990s he built the world's largest manmade bat cave on his sprawling ranch near Johnson City. For a long time, no bats showed up. Correspondent Conor Knighton reports on what happened once they did.
