Founded in 1842, the National Observatory crowns the Hill of the Nymphs opposite the Acropolis — the oldest research institution in modern Greece, in a handsome neoclassical building designed by Theophil Hansen. The original dome still houses the historic Doridis refracting telescope.
Evening visits and guided tours (book ahead) pair the astronomy with one of the best low-level views in the city, looking straight across to the floodlit Parthenon. The pine-covered hill itself, with the little chapel of Agia Marina at its foot, is a quiet corner away from the crowds.