Photo: Green Olives Market Stall Display Andalusia

A mass of green olives on display at a market stall in the old city of Cordoba in the Province of Cordoba in Andalusia, Spain.

The old city of Cordoba in Andalusia, Spain was founded in 169BC by the Romans, but olives were mentioned by Homer, who lived in the 8th century BC. The olives are quite bitter, and can be picked when they are green, as seen on the market stall, or, left on the trees until the fruit has ripened to the purple-black colour of the 'black olive'.The fruit is small in size measuring 1 to 2.5 centimeters long and a majority of the olives are harvested when they are green as they will ripen shortly after. When you see a display of canned black olives on the shelves of stores, it is probably safe to assume that they contain chemicals which would change them black artificially.Olives at a market stall in Plaza de la Corredera, City of Cordoba, UNESCO World Heritage Site, Province of Cordoba, Andalusia (Andalucia), Spain, Europe.