Man walking
(circa 1890-1891, chronophotography by Étienne-Jules Marey.)

Woman Walking Downstairs
(circa 1887 - Animated sequence of a woman walking downstairs, frames taken by Eadweard Muybridge.)

Three Duchamp brothers (Left to right: Marcel Duchamp, Jacques Villon, and Raymond Duchamp-Villon in the garden of Jacques Villon's studio in Pateaux, France, circa 1912-1914. All three participated in the 1913 Armory Show in New York. Photographer unknown.)

Marcel Duchamp playing chess
(1952, photograph by Kay Bell Reynal, from Smithsonian Institution Archives of American Art.)

Rrose Sélavy (Marcel Duchamp)
(1921. Photograph by Man Ray. Art Direction by Marcel Duchamp. Silver print.
5-7/8" x 3"-7/8". Currently @ Philadelphia Museum of Art, Philadelphia.)

Belle Haleine, Eau de Violette
(1921, reproduced in 1964, Assisted Readymade, height: 16.3 cm, width: 11.2 cm, currently in a private collection.)

Etant donnés
(1946–1966, mixed media, image of inside view of sculpture, posthumously and permanently installed in 1969 @ Philadelphia Museum of Art, Philadelphia.)

Fountain
(1917, urinal "Readymade" signed with joke name[R. Mutt], early example of "Dada" art, paradigmatic example of found-art. Photograph by Alfred Stieglitz, appeared first in 'The Blind Man' No. 2, page 4. Editors: Henri-Pierre Roche, Beatrice Wood, and Marcel Duchamp. New York, May 1917.)

Fountain
(1917, 1964 artist-authorized replica made by the artist's dealer, Arturo Schwarz, based on a photograph by Alfred Stieglitz. Porcelain, 360 x 480 x 610 mm, currently @ Tate Gallery, London.)

La mariée mise à nu par ses célibataires, même - Le Grand Verre (The Bride Stripped Bare by Her Bachelors, Even - The Large Glass)
(1915-1923, oil, varnish, lead foil, lead wire, and dust on two glass panels,277.5 cm × 175.9 cm (109.25 in × 69.25 in), Philadelphia Museum of Art, Philadelphia)

L.H.O.O.Q.
(1919, 'Mona Lisa' parody, post card reproduction with added moustache, goatee and title in pencil, 19.7 x 12.4 cm)

Nu descendant un escalier n° 2 (Nude Descending a Staircase, No. 2)
(1912, oil on canvas, 147 cm × 89.2 cm (57 7⁄8 in × 35 1⁄8 in), currently @ Philadelphia Museum of Art, Philadelphia.)

Why Not Sneeze, Rose Sélavy?
(1921, reproduced in 1964,Readymade: 152 marble cubes in the form of sugar cubes with thermometer and cuttlefishbone in a birdcage, height: 12.4 cm, width: 22.2 cm, depth: 16.2 cm, currently @ Philadelphia Museum of Art, Philadelphia.)

Artsy’s Marcel Duchamp page

Duchamp’s Readymades