Java and Bali to the east. Borneo lies to the north and Christmas Island is to the south. It is the world's 13th largest island. Java is surrounded by the Java Sea to the north, Sunda Strait to the west, the Indian Ocean to the south and Bali Strait and Madura Strait in the east. Java is almost entirely of volcanic origin; it contains thirty-eight mountains forming an east–west spine that have at one time or another been active volcanoes. The highest volcano in Java is Mount Semeru (). The most active volcano in Java and also in Indonesia is Mount
Battle of the Trench Battle of the Trench The Battle of the Trench (), also known as the Battle of the Confederates (), was a 30-day-long siege of Yathrib (now "Medina") by Arab and Jewish tribes. The strength of the confederate armies is estimated around 10,000 men with six hundred horses and some camels, while the Medinan defenders numbered 3,000. The largely outnumbered defenders of Medina, mainly Muslims led by Islamic prophet Muhammad, dug a trench on the suggestion of Salman Farsi, which together with Medina's natural fortifications, rendered the confederate cavalry (consisting of horses and camels) useless, locking the two sides in a