The word « ocean » comes from the figure in classical antiquity, Oceanus, the elder of the Titans in classical Greek mythology, believed by the ancient Greeks and Romans to be the divine personification of the sea, an enormous river encircling the world. Although many people believe that the oceans are blue because the water reflects the blue sky, this is actually not true. Water has a very slight blue color that can only be seen when there is a lot of water. However, the main cause of the blue or blue/green color of the oceans is that water absorbs the red part of the incoming light, and reflects the green and blue part of the light. We then see the reflected light as the color of water.