Original: He earned a high international profile when , in the aftermath of the killing of thirteen unarmed civilians in Derry by British Paratroopers ( known as '' Bloody Sunday '' ) , he travelled to the United Nations in New York to demand UN involvement in peace-keeping on the streets of Northern Ireland .
Simplified: After '' Bloody Sunday '' ) , he travelled to the United Nations in New York to demand UN involvement in peace-keeping on the streets of Northern Ireland .