The Grose Valley, in the centre of the Blue Mountains National Park, is regarded as the cradle of conservation in NSW. At the heart of the Grose lies the magnificent Blue Gum Forest, the site of which was the first major conservation battle in the state in 1931. Since then, almost the entire catchment has been reserved in the National Park. The main reason that the valley was able to escape development is the massive cliffs on either side. There are only a handful of easy passes into or out of the valley, and development has been limited to the cliff tops. Much of the valley has recently been preserved as wilderness, further protection for the chasms, canyons and cliffs that make up this spectacular landscape.