One of several institutions in the landmarked Union Terminal (home to the Cincinnati Museum Center), this "great" option is especially "interesting" for sometime spelunkers who are bound to appreciate the "very realistic" simulated limestone cave whose 500 feet of passageways house a live brown-bat colony; back up in the light, "be impressed by" the crevasses of a glacial ice cavern, scout the Ohio River valley of 17,000 BC or watch staffers preserve newly collected fossils.