Some superstitions are so ingrained in modern English-speaking societies that everyone, from lay people to scientists, succumb to them (or, at least, feel slightly uneasy about not doing so). But why don't we walk under ladders? Why, after voicing optimism, do we knock on wood? Why do nonreligious people "God bless" a sneeze? And why do we avoid at all costs opening umbrellas indoors?
Find out the origins of all these familiar customs, and more.