Nothing says summer quite like juicy, vine-ripened tomatoes still warm from the sun. Native to South America, tomatoes are a member of the nightshade family along with potatoes and eggplant, and were first thought to be poisonous by Europeans. It wasn’t until the twentieth century that tomatoes became a staple in the U.S., where they are now the third most popular vegetable. Although botanically a fruit, tomatoes have been classified by the U.S. government as a vegetable for trade purposes.