evidence: In the 1400s, China owned the greatest seagoing fleet in the world, up to 3,500 ships at its peak. (The U.S. Navy today has only 430). Some of them were five times the size of the ships being built in Europe at the time. But by 1525, all of China's "Treasure Fleet" ships had been destroyed -- burned in their docks or left to rot by the government. China had been poised to circumnavigate the globe decades before the Europeans did, but instead the Ming Dynasty retracted into itself and entered a 200-year-long slump. Few people in the West realise how economically and technologically advanced China was by the 1400s. The Treasure Fleet was vast -- some vessels were up to 120 metres long. (Christopher Columbus's Santa Maria was only 19 metres.) A Chinese ship might have several decks inside it, up to nine masts, twelve sails, and contain luxurious staterooms and balconies, with a crew of up to 1,500, according to one description. On one journey, 317 of these ships set sail at once.