BELGRADE: As Serbia heads to the polls Sunday, one memory looms large: the collapse of the canopy at a recently renovated railway station two years ago, which killed 16 people and launched a massive protest movement. The tragedy in the country's second city, Novi Sad, has led to the biggest challenge yet to longtime leader Aleksandar Vucic, who has stepped down as president and is seeking a return as prime minister. Ahead of the snap poll, here are the key moments that shaped Serbia's anti-co
