Former Chilean President Michelle Bachelet was 23 years old when she was tortured and fled her country’s dictatorship into exile. Now, more than four decades later, she will face her past fighting such abuses worldwide as the new U.N. human rights chief.

Bachelet, 66, is often seen smiling, chatting easily or tossing unplanned comments or jokes into her speeches. But behind her good humor lie haunting memories of the brutal dictatorship that tore her family apart.