A triptych: Eden on the left, hell on the right, and in the middle a vast garden full of naked people, giant birds, enormous strawberries and strange glass spheres. Five hundred years later, nobody agrees whether the center panel is a paradise or a warning.

Look into the right-hand panel for the “tree man”: a hollow egg-shaped body on legs like tree trunks, with a pale face looking back over his shoulder. Some think it is Bosch himself.