The border dispute between Bolivia and Chile grew slowly during most of the 19th century over the Atacama corridor, a part of the Atacama Desert which now forms northern Chile. The Atacama Desert is bordered by the Coast Range on the west and the Andes on the east. The geography of the area was a very large factor in determining how the border dispute began. Because of the mountains, the area has rains only 2 to 4 times a century, making it one of the driest places on Earth.