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
Capture of Regina Trench army division), which had been brought from the Belgian coast. On 8 October, attacks by the 1st Canadian Division and the 3rd Canadian Division on Regina Trench, also failed. On 21 October, the 4th Canadian Division attacked the western portion of Regina Trench, as the 18th Division, 25th Division and the 39th Division of II Corps, attacked the part further west (known as Stuff Trench to the British). The Canadians met little opposition and gained the objective, as the II Corps divisions captured Stuff Trench in thirty minutes, giving the British control of the Thiepval Ridge. Three counter-attacks were repulsed