Number 11, 1952 (Blue Poles)

A vast canvas teems with a dense, energetic web of poured and flung paint, and across it lean eight ragged dark-blue 'poles' that give the swirling field a wavering, rhythmic structure. Jackson Pollock made Blue Poles by dripping and pouring directly onto canvas laid on the floor, moving around it in his radical 'action painting.' Now in the National Gallery of Australia, which bought it in 1973 in a famously controversial purchase, it is among the greatest of his drip paintings - chaos and order, freedom and control, held in exhilarating, monumental balance.