With more than 17,000 islands – ranging from palm-fringed islets to the leviathan bulk of Sumatra – Indonesia's natural diversity is showcased amid more than 1.9 million sq km straddling the equator and stretching from the Indian Ocean to the Pacific. Volcanic peaks rise from lush jungle, the underwater world is revealed in the planet's finest diving locations, and surprising wildlife ranges from giant reptiles to gentle denizens of the forest.