Can you imagine a world without water, a world where there are no seas, rivers, lakes and even the rain? I am sure that you will never want to live there! You will not be able to bathe, brush your teeth, wash your clothes, quench your thirst or even go for a swim. The soil will erode and plants will die. Water is essential for all life on earth. Today we are going to be secret agents, going on a mission that will take us through a journey of understanding the existence and movement of water on, in, and above the Earth.