Thousands of Serbians block the main boulevard of the central city of Kragujevac, the latest in a series of student-led protests over the deadly collapse of a train station roof. The blockade ends with a 15-minute silence commemorating the 15 victims of the tragedy, which is widely blamed on corruption in large infrastructure projects. After an all-day rally, students clean up rubbish from the streets, just as they had done in the two previous major protests held in the capital, Belgrade, and in the northern city of Novi Sad, where the tragedy took place. IMAGES