6000-Year-Old Rock Engravings (IMAGE) University of Bonn Caption The around 6000-year-old rock engravings can hardly be seen today. They were pecked into the rock with a hard point. Credit © Photo: David Sabel Usage Restrictions This photo may be used with the press release. 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.