Originally from the Mediterranean, only the leaves were eaten historically.  The Romans were the first civilization to cultivate deeply pigmented roots for food.  We have Napoleon to thank for beets being a primary source of sugar when the passed a decree in the 19th century - The first sugar factory was built it Poland. Buy fresh beets and please eat the stems! steam them, saute them (as you would spinach) they are loaded with nutrients.  The deep purple color is a powerful pigment called betacyanin...