The Dornier Do X was the largest, heaviest, and most powerful flying boatin the world when it was produced by the Dornier company of Germany in 1929. First conceived by Dr. Claude Dornier in 1924,[1] planning started in late 1925 and after over 240,000 work-hours it was completed in June 1929.
During the years between the two World Wars, only the Soviet Tupolev ANT-20 Maksim Gorki landplane of a few years later was physically larger, but at 53 metric tons maximum takeoff weight it was not as heavy as the Do X's 56 tonnes.