A junk is a boat used in China. Junks usually have around two or three sails but sometimes have four. Each mast is made of bamboo. Bamboo is used because it is so strong that you don’t need very many ropes. Very large junks (about 150 meters or 492 feet long) are usually used for worldwide trips. An average sized junk usually carries food from city to city. The first Chinese junks were built in the Song dynasty between 960-1270. Later, in 1271-1368 a Mongol emperor built the first Chinese imperial treasure fleets. These junks sailed to Sumatra, Ceylon, and southern India. The famous explorer, Marco Polo journeyed to the Mongol court and described seeing four-masted junks that had sixty cabins for merchants and crews of up to 300. About six centuries ago, the Chinese built huge armadas of junks that sailed to Ceylon, Arabia, and East Africa. The fleet had huge nine-masted junks that were over 400 feet long and 150 feet wide or 122 meters long and 46 meters wide. There were 27,000 crew members and soldiers in the armada! These junks were escorted by water tankers, supply ships, ships for cavalry horses, and patrol boats.