The largest island that fully belongs to Indonesia, Sumatra stretches alongside the whole of West Malaysia, past Singapore and all the way south to the Sunda Strait that separates it from Java. The island is of great cultural and economical importance for Indonesia and known for its incredible nature with some of the most stunning volcanoes on earth, including the Krakatoa. Not surprisingly, visitors can also find the largest volcanic lake in the world here, Lake Toba. Significant cities include Medan, Palembang, Pekanbaru and Padang just to name a few.