Human beings have often sought to give concrete form to our powerful collective longing for peace. After World War I, that longing led to the League of Nations and numerous rules and taboos designed to govern warfare itself. Of these, the most important was the proscription against attacking and killing civilian non-combatants even in times of war. However, the second half of the twentieth century has seen most of those taboos broken. Guernica was the point of departure, and Hiroshima is the ultimate symbol. We must find ways to communicate to future generations the history of horror that began with Guernica...<br>