When Beatrice Fihn received a call on Oct. 6 informing the 35-year-old Swede that her group, the International Campaign to Abolish Nuclear Weapons (ICAN), had been awarded the Nobel Peace Prize, she suspected a possible prank. Not that you should blame her—ICAN is just 10 years old, and the group’s aims can seem positively fanciful: the complete elimination of the world’s roughly 15,000 nuclear warheads.