Jonas Salk wasn't seen as a brave hero―not at first. As a child he was quiet and unassuming, but Jonas dreamed of tikkun olam, the Jewish phrase for “healing the world.” He saw the polio virus strike his city, and he knew that with determination and hard work, he could be the one to stop its spread. So he grew up to study medicine, ultimately creating the polio vaccine that saved untold numbers of lives―and healed the world!