Former United Nations (UN) chief and Nobel peace laureate Kofi Annan died Saturday at the age of 80, triggering a flood of tributes from around the world for the "diplomatic rock star".The Ghanaian national was a career diplomat who projected quiet charisma and was widely credited for raising the world body's profile in global politics during his two terms as head of the UN from 1997 to 2006.The first secretary general from sub-Saharan Africa, Annan led the UN through the divis