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
Podtatrzański Trench glacial periods. The western part and eastern borderlands of the Podtatrzański Trench are forested. The main brooks that drain through the valley are the Czarny Dunajec, as well as the Zakopianka and Poroniec (sourced from the Biały Dunajec). The region is characterised by the settlement areas of Zakopane, as well as Kościelisko, Małe Ciche and Murzasichle. Podtatrzański Trench Podtatrzański Trench (Polish: Rów Podtatrzański; Slovakian: Podtatranská brázda) (514.14) - a mesoregion located below the Tatra Mountains, part of the Orava-Podhale Depression. The trench divides the Choč and Tatra Mountains from the Spisko-Gubałowski Plateau. The region is located between 700 and 1000