Apples are arguably the world's most popular fruit -- "the apple of my eye," "as American as apple pie," "an apple a day keeps the doctor away." In many languages, other fruits and vegetables are defined in terms of apples, like pommes de terre in French and sib zamini in Farsi for potatoes, and the Medieval name "love apples" for tomatoes. And let's just say you won't find watermelons in the origin stories of multiple religions.