Jackson Pollock, 1948. Drip-poured enamel on canvas spread across his Long Island barn floor. MoMA, New York.
From Wikipedia
No. 5, 1948 is a 1948 painting by Jackson Pollock, an American painter known for his contributions to the abstract expressionist movement. It was sold on 22 May 2006 for $140 million, a new mark for highest ever price for a painting, not surpassed until April 2011.