Our silver peace charm is associated with pacifism. The sign has become propagated by American hippies with slogan "make love, not war!" as a symbol of harmony, peace and nuclear disarmament.
It is officially explained that the symbol consists letters N and D, put one on another (from the phrase nuclear disarmament), surrounded by a circle as a symbol of the world. Hippies believed that sign looks like a rose or a fist breaking a rifle.