The largest battleship ever built is the Japanese battleship Yamato. It was commissioned in 1941 and was the flagship of the Imperial Japanese Navy during World War II. The Yamato had a displacement of around 72,800 tons and was 263 meters (863 ft) long, it was armed with nine 18.1-inch (460mm) guns, the largest guns ever mounted on a battleship, and had a crew of around 2,500.
The Yamato was built to be the most powerful battleship of its time, it was heavily armored and had an advanced fire control system. However, despite its size and power, the Yamato saw limited action during World War II and was ultimately sunk by American carrier-based aircraft in April 1945.
Other notable contenders for the title of the largest battleship include the German battleship Tirpitz, the American battleship Iowa class, and the British battleship Vanguard.
It’s important to note that battleships were built for different purposes and each country’s Navy has its own requirements and priorities, therefore, the largest battleship is a relative term and the size and capabilities of battleships can vary. Also, the era of battleship as the main naval power came to an end with the advent of aircraft carriers and submarines, which made battleships less useful in the naval warfare, and they were mostly replaced by aircraft carriers as the main capital ship in the navy.