Today, on the 75th anniversary of the bombing of Guernica, we republish a video of a speech by Alan Woods, of the International Marxist Tendency. The speech was made  to University of Arts' London students at the Whitechapel Gallery, London, where a replica of Picasso's great painting of the massacre at Guernica was on display. Using this powerful masterpiece as a starting point, Alan explores what makes great art; to what extent is great art a reflection of the period from which it comes; and can propaganda be great art?