The central axis of the garden is extended, beyond its wrought iron grill and gates opening to rue Auguste Comte, by the central esplanade of the rue de l'Observatoire, officially the "Jardin Marco Polo", where sculptures of the four "Times of Day" alternate with columns and culminate at the southern end with the 1874 "Fountain of the Observatory", also known as the "Fontaine des Quatre-Parties-du-Monde" or the "Carpeaux Fountain", for its sculptures by Jean-Baptiste Carpeaux.