Observatoire de Paris

Built between 1667 and 1672 by architect Claude Perrault, the Paris Observatory is an emblematic historic building housing a collection of astronomical instruments. It is also the oldest observatory in operation. The meridian of France, established in 1729 by Jacques Cassini, was created here, enabling the first map of France to be drawn. In 1884, an international convention chose the Greenwich meridian as the universal geographic reference.