He was noted for the humanitarian assistance and safe passages that he arranged for over 2,000 people including over 375 children fleeing violence during this time.
Costa was born in Mestre, a borough of Venice in Italy, on 7 May 1939, to Mariangela (née Colombo) and Pietro Giuseppe.
[5] During Costa's time in the Congo, he witnessed the 1960 violence in Bukavu where he arranged for transportation of Congolese refugees across Lake Kivu.
[3] He moved to his brother's house in Burundi during this period; from there, he traveled back and forth from Rwanda to arrange for the rescue and safe passage for those impacted by the violence.
He began by helping evacuate Italians and citizens of other western nations, but he soon started arranging passage for persecuted Rwandan Tutsis as well.
[3][5] He used his diplomatic permissions to arrange for exit permits for those fleeing the violence[3][6] He dealt with local militiamen while crossing the checkpoints between Rwanda and Burundi.
[5] For his role in providing humanitarian assistance during the conflict, he was nominated - along with two Rwandan women Zura Karuhimbi and Yolande Mukagasana - for the 2011 Nobel Peace Prize.