It bears all the hallmarks of a beautifully composed painting - the balance between light and dark, the diagonal paths leading you through the picture, the twin-curve poise of the main subjects and their characterful expressions.
Yet it has been executed in a fraction of a second.
Candid photography in its highest form combines the artist's eye with the speed of decision-making and technological dexterity of a formula racing driver. Henri Cartier-Bresson, who took this picture in Holland in 1956, says it happens so fast it has to be intuitive. The skill is in training your mind, heart and hand to work together instantly to capture the decisive moment: "Suddenly you see a rigorous geometry of forms and you have an instant drawing. It's nothing more for me."
Cartier-Bresson, 90 this August, is widely regarded as the greatest living photographer. Trained in drawing, he was influenced by surrealist and communist ideas and produced pictures that commented on the human condition often with a witty eye for the unexpected.
An escaped prisoner of war, he fought for the French Resistance and in 1947 co-founded Magnum Photos with Robert Capa. He roamed the world documenting life and witnessing historic moments - he was in Cuba during the missile crisis; he met Gandhi an hour before he was assassinated - until he officially retired from photography 25 years ago. But he was compulsively modest about his ability. "One must not take photographs," he once said. "It is the photograph which takes you."