The Democratic Peace thesis suggests that the absence of war between major powers since 1945 is caused by the spread of democracy. The Capitalist Peace thesis emphasizes trade and the rise of knowledge economies as the forces driving peace. Complementing these interpretations, we present empirical evidence of a cultural change that is making peace more desirable to the publics of most societies around the world. Analyzing public opinion data covering 90% of the world’s population over three decades, we demonstrate that improving existential conditions elevate the life opportunities of growing population segments and lead them to become increasingly tolerant of diversity and place growing emphasis on self-realization. In recognition of life’s rising opportunities, people’s valuation of life changes profoundly: readiness to sacrifice one’s life gives way to an increasing insistence on living it, and living it the way one chooses. Hence, pro-choice values rise at the same time as willingness to sacrifice lives in war dwindles. Historical learning based on the specific experiences of given societies has also changed their publics’ willingness to fight in wars. This transformation of worldviews places interstate peace on an increasingly solid mass basis.