The mayor of Greece’s second-largest city, Thessaloniki, was treated in hospital after he was beaten up by nationalist extremists. Mayor Boutaris had been at an event commemorating the killing of ethnic Greeks by Turks.Boutaris was being escorted from an event that commemorated the massacre of Black Sea Greeks, when members of the crowd turned violent. Footage showed the 75-year-old Thessaloniki mayor being heckled by dozens of people as he left the event on Saturday evening. Bottles were thrown at Boutaris, who is known for his strong anti-nationalist stance, before he fell down and was kicked and punched in the head...