The watermelon, a part of summer cookouts and picnics, once was a bitter little fruit about two inches in diameter, writes Rebecca Rupp in a National Geographic blog post. “Today, due to countless creative generations of breeders, the watermelon averages over two feet in diameter – a 1,680-fold increase in volume over its many-times-great-grandparent – and weighs in somewhere between four and 18 pounds,” says Rupp, citing one scientist’s assessment that human intervention has made the melon the most unnatural fruit in the world. Watermelons are high in lycopene, an antioxidant with healthful benefits. “In other words, when it comes to watermelon, feel free to dig in,” she writes.