#7 World Largest Island in an Island

The island of Samosir inside Lake Toba, North Sumatra, is the world largest island in an island. With an area of 243 square kilometre, this island is bigger than the neighboring country, Singapore. Samosir island great size makes it visible even from outer the space.

Samosir island and its surrounding actually have a fascinating history. It lies on the greatest supervolcano in existence in the surface of earth, the Toba supervolcano. Since its cataclysmic eruption, magma has continuously refilling the empty magma chamber which uplift the Samosir island for more than 450 metres (1,476 feet).

Source:
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Supervolcano: 

The Catastrophic Event That Changed the Course of Human History: Could Yellowstone Be Next. John Savino, Marie D. Jones. page 118. Career Press, 2007