Britain‘s Prime Minister Theresa May signs the official letter to European Council President Donald Tusk, in 10 Downing Street, London, Tuesday March 28, 2017, invoking Article 50 of the bloc’s key treaty, the formal start of exit negotiations. Britons voted in June to leave the bloc after four decades of membership. (Christopher Furlong/Pool Photo via AP) <저작권자(c) 연합뉴스, 무단 전재-재배포 금지>