When Wilbur Scoville first devised a means to test the heat of peppers, his hottest entry then came in at 20,000 units. Habanero and Thai chilies can go as high as 60,000. Compare that to the sweet bell pepper at zero. It is thought that all peppers, hot and sweet, developed from the wild chiltepin pepper of Central America. Although a perennial, they are widely grown as annuals. Columbus is credited with bringing peppers back to Spain, as a substitute for true pepper (Piper nigrum).