The Jet d'Eau in Geneva is one of the tallest fountains in the world, shooting water 140 meters into the air. It was not originally intended to be a monument; in 1886, it was installed as a safety valve for a hydraulic power network that provided energy to the city's jewelers and watchmakers. When the artisans finished work at night, the pressure in the system would build up, so the valve was opened to release it, creating a jet of water. It became so popular with the public that the city moved it to its current location in Lake Geneva and turned it into a permanent landmark. Today, two massive 500-kilowatt pumps propel 500 liters of water per second at a speed of 200 km/h, meaning there is roughly 7,000 liters of water in the air at any given moment.