Sumatra or Sumatera, is the sixth largest island of the world (approximately 470,000 sq km) and is part of Indonesia.
The longest axis of the island runs approximately northwest - southeast, crossing the equator near the center. The interior of the island is dominated by two geographical region: the Barisan Mountains in the west and swampy plains in the east.
To the southeast is Java, separated by the Sunda Strait. To the north is the Malay Peninsula, separated by the Straits of Malacca. To the east is Borneo, across the Karimata Strait. West of the island is the Indian Ocean.
The backbone of the island is the Barisan mountains chain. The volcanic activity of this region endowed the region with fertile land and beautiful sceneries, for instance around the Lake Toba. It also contain deposits of coal and gold.
To the east, big rivers carry silt from the mountain, forming the vast lowland interspersed by swamps. Even if mostly unsuitable for farming, the area is currently of great economic importance for Indonesia. It produces oil "from above the soil and underneath": the palm oil and petroleum.
Most of Sumatra used to be covered by tropical rainforest, home to species such as orangutans, tapirs, and Sumatran tigers, and some unique plants like the Rafflesia. Unfortunately, economic development coupled with corruption and illegal logging has severely threatened its existence. Conservation areas has not been spared by destruction, either.
See also: Islands of Indonesia, Riau islands, Rengat
An ancient name for Sumatra was Swarna Dwipa, (that's Sanskrit for Isle of Gold), apparently based on the fact that mines in the Sumatran highlands were exporting gold from fairly early times.
With its location in the India-China sea trade route, several trading towns flourished, especially in the eastern coast, and were influenced by Indian religions. The most notable of these is the Srivijaya, a Buddhist monarchy centered in what is now Palembang. Dominating the region through trade and conquest throughout the 7th-9th century, the kingdom helped spreading the Malay culture throughout Sumatra, Malay Peninsula, and western Borneo. The empire is thalassocratic, though, meaning that it didn't extend its influence far beyond the coastal area.
Srivijaya influence waned in the 11th century. The island was then subject to conquests from Javanese kingdoms, first Singhasari and subsequently Majapahit. At the same time, Islam made its way to Sumatra, spreading through contacts with Arabs and Indian traders.
By the late 13th century, the monarch of Samudra kingdom (now in Aceh) has converted to Islam. Ibn Battuta, who visited the kingdom during his journey, pronounced the kingdom "Sumatra", hence the name of the island. Samudra was succeeded by the powerful Aceh Sultanate, which survived to the 20th century. With the coming of the Dutch, the many Sumatran princely states gradually fell under their control. Aceh in the north was the major obstacle, as the Dutch were involved in the long and costly Aceh War (1870-1905).
Sumatra is not very heavily populated, about 85 people per sq.km (with more than 40 million people in an area the size of Germany). The most populous regions includes most of Sumatra Utara and central highland in Sumatra Barat, while the major urban centre are Medan and Palembang.
The people are of Malay stock composed of many different tribes, speaking 52 different languages. Most of these groups, however, share many similar traditions and the different tongues are closely related. Malay-speaking people dominate the eastern coast, while people in the southern and central interior speak languages related to Malay, such as Lampung and Minangkabau. The highland of northern Sumatra is inhabited by the Bataks, while the northernmost coast is dominated by Acehs. Ethnic Chinese minorities are also present in urban centers.
A majority of people in Sumatra are Muslims. Most central Bataks, meanwhile, are Protestant Christians - the religion was spread by the Dutch. The rest follow Hinduism, Buddhism, Catholicism, and Chinese traditional beliefs.