Like potatoes, tomatoes, and corn, the cheerful plants didn't originate in Europe. They were cultivated in North America as far back as 3000 BCE, when they were developed for food, medicine, dye, and oil. Then, they were exported to the rest of the world by Spanish conquistadors around 1500.
Sunflowers have been planted to help soak up nuclear radiation. They're not just pretty faces; sunflowers are actually good at absorbing toxins, too. Millions were planted after the devastating tsunami destroyed reactors in the Fukushima nuclear power plant in Japan.