More than 100,000 demonstrators marched against corruption under President Aleksandar Vučić in Belgrade on Saturday. Observers talk of this being the biggest popular rally since the fall of Slobodan Milošević 25 years ago. The months-long unrest was triggered by the fatal collapse of a roof at Novi Sad train station, which has been blamed on shoddy construction and cronyism. Europe's press chimes in.