The country consists mainly of a plateau between 700 meters and 1,200 meters high, divided into ridges by valleys and gorges, and a few mountainous areas. West of the plateau, land descents form the East Bank of the Jordan Rift Valley. The valley is part of the north-south Great Rift Valley, and its successive depressions are Lake Tiberias (Sea of Galilee; its bottom is about −258 meters), Jordan Valley, the Dead Sea (its bottom is about −730 meters), Arabah, and the Gulf of Aqaba at the Red Sea. Jordan's western border follows the bottom of the rift. By far the greatest part of the East Bank is desert, displaying the land forms and other features associated with great aridity. Most of this land is part of the Syrian Desert and northern Arabian Desert. There are broad expanses of sand and dunes, particularly in the south and southeast, together with salt flats. Occasional jumbles of sandstone hills or low mountains support only meager and stunted vegetation that thrives for a short period after the scanty winter rains. These areas support little life and are the least populated regions of Jordan.