Medan, the capital of North Sumatra, is on the northern part of Sumatra. It is the fourth largest city in Indonesia after Jakarta, Surabaya, and Bandung. With a population of about 2 million people it is the largest city outside of Java. There is no single ethnic group forming a majority; the largest ethnic groups are the Chinese, Javanese, Toba-Batak, Minangkabau, Mandailing Batak, Karo Batak, Southern Indians, and Northern Indians, and there are many more ethnic minorities.
It's interesting to contrast the old, Dutch style green areas, with parks, lawns, and huge old Dutch houses (now turned into government offices or commercial business) and the hundreds and hundreds of newer, shoddy shophouses sprawled together by the hundreds in the commercial areas along with a few modern style malls.