Meudon observatory. The building was originally a castle built in the early 17th century, and turned into an observatory in 1876. Meudon observatory. The building was originally a castle built in the early 17th century, and turned into an observatory in 1876. Park of the former castle of Meudon. Park of the former castle of Meudon. Hall "Y", built in 1889, to host research on aviation. The first closed-loop airship flight took place there in 1884. Meudon. Furniture from the destroyed Meudon palace. Napoleon era. Marly-le-RoiMonte-Cristo Castle Labels