The Zumwalt-class destroyer is a class of United States Navy guided missile destroyers designed as multi-mission stealth ships with a focus on land attack. The class emerged from the previous DD-21 vessel program, previously known as the "DD(X)". The class is multi-role and designed for surface warfare, anti-aircraft warfare, and naval gunfire support. They take the place of battleships in filling the former congressional mandate for naval fire support, though the requirement was reduced to allow them to fill this role. The vessels' appearance has been compared to that of the historic ironclad warship.