In Western Australia, thousands of salt lakes follow the tracks of ancient river systems. This area has been shaped millions of years by climate and geology, when rainfall declined, the river started to dry and the river bed filled up with sediments. The wind then sculpted circled salt lakes which are dry for most of the year. When there is enough rainfall, the salt lakes become an active river system again. Many of the lakes have very high salt concentration due to the high amount of minerals in the ground.