Some surprises in Madrid

• Fingerprints on the edge of a Mondrian canvas
• The date on Ivan Wasilewitsch’s painting of a green triangle on white ground. 1917
• The impact of Guernica and the erratic buzzing as people set off an alarm as they crossed the security line
• Miro's elegant line, and how good he can be
• The strange familiarity of some of the paintings in the Thyssen-Bornemisza collection thanks to the National Art Gallery's exhibition from the collection in the 80s
• The bleakness of Goya’s Two men fighting with clubs
• The rapacious black dog in Botticelli’s The infernal hunt
Image: The closest we could get to photographing Picasso's Guernica at the Reiner Sofia