Episode 1: Source of Life

Barely three percent of our water is freshwater. How much water actually exists on Earth? NASA researchers try to find out how water actually arrived on Planet Earth. In South Africa, researchers search for the oldest body of water in the world. Only a fraction of our freshwater reserves are in the clouds. And yet clouds and rain are what keep the cycle of life going. When do clouds turn into rain? And how does the eternal cycle of water work?