 Exhibits include life-size replicas of the Best Friend of Charleston- the first American-built locomotive in 1830; and the Civil War's H.L.Hunley, the first submarine to sink an enemy ship in combat.The second floor on natural history is notable for its recreation of a 3.6 million-year-old Megalodon, named Finn, suspended mid-air just around a corner, which has scared countless groups of young children, and for a life-size Columbian mammoth (which was once native to SC).