Mount Tambora (or Tamboro) is an active stratovolcano which is a peninsula of the island of Sumbawa in Indonesia. Sumbawa is flanked both to the north and south by oceanic crust, and Tambora was formed by the active subduction zone beneath it. This raised Mount Tambora as high as 4,300 m (14,100 ft), making it one of the tallest peaks in the Indonesian archipelago in the 18th century.