Thousands of demonstrators massed on streets surrounding Istanbul's central Taksim Square, long a venue for political unrest, while protests erupted in the capital Ankara and the Aegean coastal city of Izmir. Broken glass and rocks were strewn across a main shopping street near Taksim. Primary school children ran crying from the clouds of tear gas while tourists caught by surprise scurried to get back to luxury hotels lining the square. The unrest reflects growing disquiet at the authoritarianism of Prime Minister Tayyip Erdogan and his Islamist-rooted Justice and Development Party (AKP). Riot police clashed with tens of thousands of May...