Dead Vlei is considered a white clay bowl located within the Namib-Naukluft Park near to Sesriem in Namibia. Dead Vlei has been hailed as being surrounded by the world's largest sand dunes, where the largest of them, known as "Big Daddy" or "Crazy Dune", reaches the astonishing height of 300 to 400 meters. However, on this topic there are still long discussions; It is only known that Dead Vlei has some of the largest known dunes, but not if in fact Big Daddy is the largest in the world. As for the white clay soil, this was formed after a great precipitation, when the Tsauchab River flooded forming shallow and temporary pools, where the abundance of water allowed a species of acacia (Acacia erioloba) to develop. However, the occurrence of some climate changes caused sand dunes to invade the area by the river, preventing it from reaching the region. This, therefore, caused a great aridity, and transformed the place in what today is known as Dead Vlei.