For as long as ships have been around, naval powers have competed for supremacy on the seas. After the steam engine's invention in the 19th century, warship design underwent a major upheaval, culminating in an arms race for the best battleships and cruisers. Some of these ships went on to become famed World War I and II icons. Others never made it past the blueprint stage. You'll find that when it comes to naval warfare, the Popular Sciencearchives favor both the formidable and the funny speculations, as long as they contribute to a bright (Allied) future.