Malay Archipelago

The Malay Archipelago refers to the archipelago between mainland Southeastern Asia and Australia.
It has also been called the East Indies, the Indo-Australian Archipelago, Indonesian Archipelago and other names over time. 
The archipelago is between the Indian and Pacific Oceans. The group has over 25,000 islands. It is the largest archipelago by area, and third by number of islands in the world. It includes Indonesia, the Philippines, Singapore, Brunei, East Malaysia and East Timor. 
The island of New Guinea or islands of Papua New Guinea are not always included in definitions of the Malay Archipelago. The Indonesian Moluccas are included in the archipelago.
Natural history.
The Malay Archipelago is the place where two large tectonic plates meet, and is an area where orogeny (mountains) and volcanoes are common. 
The Wallace Line is a key term in biogeography. It passes between Bali and Lombok, which are separated by a passage of water which is both deep and fast. On the one side are Australasian species, and on the other side Asian species. The natural history of the area was investigated by Alfred Russel Wallace, who spent eight years in the Spice Islands.