2971378 Le Neptune, Place Saint-Pierre ? Montmartre, September 23, 1870 (gelatin silver printing out print) by Nadar, (Gaspard Felix Tournachon) (1820-1910); 10.1x7.4 cm; The Art Institute of Chicago, IL, USA; (add.info.: During the Siege of Paris, lasting from 19 September 1870 to 28 January 1871, balloons were the only means of send mail to the outside world.); Julien Levy Collection, Gift of Jean Levy and the Estate of Julien Levy.