Natural elements, before the deluge, some evil had been subjected to big fire to be destroyed in the time of Methuselah, then the evil had been subjected to big water (combined with hell fire since the water probe the oblivion) in noah time. Hence some evil only has been watched by fire, some evil only has been watched by water, then they has been blessed us for purification, then in the prophet Mohamed time (PBO) the mercy of earth has been granted for the purification. Hence we have been blessed by water, fire and earth for purification But what has been told in the Hadith is that if you witness water you have always use water to make Wudu.......inspiration might be above