So tragic, so sad --big loss to the Russian nation and the world especially the artistic community.  Alexandrov's 
Choir was one of the  greatest. I saw it in Edmonton a long time ago. Mitchell Sharp, then foreign minister said that their singing of O Canada--was the best he ever heard--Many agreed with him. "Suliko" as sung by them also comes to mind.  Our condolences to all the loved ones. Our thoughts and prayers are with you.