<P> Unlike the Pacific Ocean where the civilization of the Polynesians reached most of the far flung islands and atolls and populated them, almost all the islands, archipelagos and atolls of the Indian Ocean were uninhabited until colonial times . Although there were numerous ancient civilizations in the coastal states of Asia and parts of Africa, the Maldives were the only island group in the Central Indian Ocean region where an ancient civilization flourished . Maldivian ships used the Indian Monsoon Current to travel to the nearby coasts . </P> <P> From 1405 to 1433 Admiral Zheng He led large fleets of the Ming Dynasty on several treasure voyages through the Indian Ocean, ultimately reaching the coastal countries of East Africa . </P> <P> In 1497 Portuguese navigator Vasco da Gama rounded the Cape of Good Hope and became the first European to sail to India and later the Far East . The European ships, armed with heavy cannon, quickly dominated trade . Portugal achieved pre-eminence by setting up forts at the important straits and ports . Their hegemony along the coasts of Africa and Asia lasted until the mid 17th century . Later, the Portuguese were challenged by other European powers . The Dutch East India Company (1602--1798) sought control of trade with the East across the Indian Ocean . France and Britain established trade companies for the area . From 1565 Spain established a major trading operation with the Manila Galleons in the Philippines and the Pacific . Spanish trading ships purposely avoided the Indian Ocean, following the Treaty of Tordesillas with Portugal . By 1815, Britain became the principal power in the Indian Ocean . </P> <P> Opening of the Suez Canal in 1869 revived European interest in the East, but no nation was successful in establishing trade dominance . Since World War II the United Kingdom was forced to withdraw from the area, to be replaced by India, the USSR, and the United States . The last two tried to establish hegemony by negotiating for naval base sites . Developing countries bordering the ocean, however, seek to have it made a "zone of peace" so that they may use its shipping lanes freely . The United Kingdom and United States maintain a military base on Diego Garcia atoll in the middle of the Indian Ocean . </P>

Which oceans have the greatest number of rivers flowing into them