The Zambezi River winds through eastern Africa, providing much-needed water to plants and animals there. But during the dry season, when rain and river water are scarce, most trees go bare. The apple ring acacia is the exception. These towering trees rely on their taproot, which delves 30 meters or more into the ground, to deliver an ongoing supply of water. Flush with water, the trees remain green, providing vital food and shade to animals during the harshest season of the year. (Image and video credit: BBC Earth)