The Dornier Do X was the largest, heaviest and most powerful flying boat in the world when it was produced by the German Dornier company in 1929. The aircraft was conceived by Dr. Claudius Dornier and took seven years to design and another two years to build. In the design process, a one-to-one wooden mock-up, the first in aviation history, was built.
It was financed by the German Transport Ministry and was manufactured in a specially designed plant at Altenrhein, on the Swiss portion of Lake Constance, in order to circumvent the Treaty of Versailles, which forbade aircraft to be built in Germany after World War I.
While popular with the public, a lack of commercial interest and a number of (non-fatal) accidents prevented more than three models from being built.