LEIDEN.- Dutch Photographer Erwin Olaf presents his photo project on the theme, Relief of Leiden, at the Lakenhal Museum in Leiden, The Netherlands, 28 September 2011. The artwork is presented as part of an exhibition, entitled Vrijheid! Leidens Ontzet 1574-2011 (Freedom! Relief of Leiden 1574-2011), that explores the Siege of Leiden which occurred during the Eighty Years War in 1573 and 1574, when the Spaniards attempted to capture the rebellious city of Leiden and failed. The exhibition opens to the public from 30 September 2011 to 08 January 2012. EPA/ROBERT VOS.