High Quality Content by WIKIPEDIA articles! The Nullarbor Plain is part of the area of flat, almost treeless, arid or semi-arid country immediately north of the Great Australian Bight. The word Nullarbor is derived from the Latin nullus, "no", and arbor, "tree", and is pronounced /?n?l?b?r/ NUL-?r-bor. It is the world's largest single piece of limestone, and occupies an area of about 200,000 square kilometres (77,000 sq mi)[1]. At its widest point, it stretches about 1,100 kilometres (684 mi) from east to west between South Australia (SA) and Western Australia (WA).