Thera Fresco (IMAGE) Princeton University, Engineering School Caption This is one of the reassembled wall mosaics from the ancient Greek civilization Thera, which was buried under volcanic ash more than 3,500 years ago. Credit Princeton Graphics Group 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.