Surabaya (formerly Soerabaja) is Indonesia's second-largest city, and the capital of the province of East Java. It is located on the northern shore of eastern Java at the mouth of the Mas River and at the side of the Madura Strait. Known as the city of heroes, because of its heroic role in the history of Indonesia. In 2007, the population of the city is approximately 3 million. The city is one of the busiest ports in the country.