Water a component of the Four Elements considered by the ancient philosophers as essential for survival, played, and is still playing an essential role in society. Great civilizations in ancient times developed along great rivers. The ancient peoples knew how to manage water supplies by digging canals, controlling floods, and using water for irrigation. They designed equipment that used water to measure the time, to determine the density of solids, to fight fires, and to create vacuum. Modern engineers exploited water flow to design and construct huge hydroelectric power stations. Waterways and navigation systems were also an essential element for the development of our civilization. In modern times water towers were constructed for water distribution in cities. In addition, fountains were commissioned by rich people and royalties throughout the centuries as an artistic attraction, but this had a great impact on the development of aqua science. Even in modern times elaborate fountains are being constructed. Mermaids and nymphs have been an interesting topic for artists. To-day controlling water pollution and studying the oceans are the concern of modern chemists and engineers.