With the successful crossings of the Atlantic in 1919 by the U.S. Navy's NC-4 and Alcock and Brown in a Vickers Vimy, circumnavigation of the globe by airplane was a natural next challenge. In July 1923, U.S. Army Air Service disclosed that it intended to attempt a global flight the following year. Four specially built aircraft were commissioned from the Douglas Aircraft Company. The World Cruisers, as they were called, were christened the Seattle, the Chicago, the Boston, and the New Orleans. Only the New Orleans and the Chicago completed the arduous 44,085 km (27,553 mi) flight. It took 175 days, with a flying time of 371 hours 11 minutes.