Indonesia is a country in Southeast Asia. Comprising 17,508 islands, it is the world's largest archipelagic state. The five largest islands are Java, Sumatra, Kalimantan (the Indonesian part of Borneo), New Guinea (shared with Papua New Guinea), and Sulawesi. With a population of 222 million people, it is the world's fourth most populous country and the most populous Muslim-majority nation. Indonesia is a republic, with an elected legislature and president. The nation's capital city is Jakarta. Across its many islands, Indonesia consists of distinct ethnic, linguistic, and religious groups. Despite its large population and densely populated regions, Indonesia has vast areas of wilderness that support the world's second highest level of biodiversity. Indonesia's location on the edges of the Pacific, Eurasian, and Australian tectonic plates makes it the site of numerous volcanoes and frequent earthquakes. Indonesia has at least 150 active volcanoes, including Krakatoa and Tambora. Bali is an island in Indonesia and has gained popularity as an island get-away.