A monumental hall, 8,000 square meters, observing instruments, a giant dome… The three sites of the Observatoire de Paris harbor treasures brimming with history, and are vibrant places turned towards the future. Discover the Paris campus, founded in 1667; the Meudon campus, created in 1875, and associated with the Paris Observatory in 1927; and Nançay, the radio-astronomical observatory built in 1953 in the heart of the forest in the Cher region.