Medieval Walls in Granada, Spain (IMAGE) American Chemical Society Caption Scientists have found a 14th century oven used to bake animal bones for the purpose of strengthening the grand medieval walls in what is today, Granada, Spain. Credit Credit: American Chemical Society Usage Restrictions None License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.