At the most westerly point of the Australian continent, Shark Bay, with its islands and the land surrounding it, has three exceptional natural features: its vast sea-grass beds, which are the largest (4,800 km2) and richest in the world; its dugong (‘sea cow’) population; and its stromatolites (colonies of algae which form hard, dome-shaped deposits and are among the oldest forms of life on earth). Shark Bay is also home to five species of endangered mammals.

Źródło: World Heritage Convention
http://whc.unesco.org/en/list/578