Semeru, also Mount Semeru or Gunung Semeru - located in East Java is the highest mountain on the island of Java, Indonesia. The stratovolcano is also known as Mahameru, meaning 'The Great Mountain'.

Java (Indonesian: Jawa) is an island of Indonesia and the site of its capital city, Jakarta. Once the center of powerful Hindu-Buddhist kingdoms, Islamic sultanates, and the core of the colonial Dutch East Indies, Java now plays a dominant role in the economic and political life of Indonesia. Home to a population of 130 million in 2006, it is the most populous island in the world, ahead of Honshū, the main island of Japan. Java is also one of the most densely populated regions on Earth.

Formed mostly as the result of volcanic events, Java is the 13th largest island in the world and the fifth largest island in Indonesia. A chain of volcanic mountains forms an east-west spine along the island. It has three main languages, though Javanese is dominant and is the native language of 60 million people in Indonesia, most of whom live on Java. Most residents are bilingual, with Indonesian as their second language. While the majority of Javanese are Muslim, Java has a diverse mixture of religious beliefs and cultures.

The Republic of Indonesia (pronounced /ˌɪndoʊˈniːziə/ or /ˌɪndəˈniːʒə/) (Indonesian: Republik Indonesia) is a country in Southeast Asia and Oceania. Indonesia comprises 17,508 islands. With a population of around 230 million people, it is the world's fourth most populous country, and has the world's largest population of Muslims. Indonesia is a republic, with an elected legislature and president. The nation's capital city is Jakarta. The country shares land borders with Papua New Guinea, East Timor, and Malaysia. Other neighboring countries include Singapore, Philippines, Australia, and the Indian territory of the Andaman and Nicobar Islands.

The Indonesian archipelago has been an important trade region since at least the seventh century, when Srivijaya and then later Majapahit traded with China and India. Local rulers gradually adopted Indian cultural, religious and political models from the early centuries CE, and Hindu and Buddhist kingdoms flourished. Indonesian history has been influenced by foreign powers drawn to its natural resources. Muslim traders brought Islam, and European powers fought one another to monopolize trade in the Spice Islands of Maluku during the Age of Discovery. Following three and a half centuries of Dutch colonialism, Indonesia secured its independence after World War II. Indonesia's history has since been turbulent, with challenges posed by natural disasters, corruption, separatism, a democratization process, and periods of rapid economic change.