One of the first signs visitors encounter at most museums is, "Please do not touch the exhibits." However at the new "Hoy toca el Prado" (Come touch the Prado) exhibition at Madrid's Museo Nacional Del Prado, the officials don't just encourage the habit, they insist upon it. That's because this unique art display has been specially created to enable visually impaired patrons to experience the joy of the works of some of the world's most famous artists, just like non-disabled people can.