Marcel Duchamp submitted a urinal to an art exhibition in 1917, signed it "R. Mutt," and called it Fountain. Then he announced he had given up art to play chess. For twenty-five years everyone believed him. After his death, they discovered he had been secretly working on a final installation the entire time — a peephole revealing a nude figure in a landscape that no one had known existed.

This episode traces Duchamp from Nude Descending a Staircase through the readymades, his chess obsession, and the secret masterwork that revealed his retirement as the greatest performance of his career.

• Fountain, a porcelain urinal submitted to a 1917 exhibition, is considered one of the most influential artworks of the twentieth century
• He secretly spent twenty years creating his final work, Etant donnes, while the world believed he ha ...