Figures Zhang et al (IMAGE) PNAS Nexus Caption (A) Overview of the Silk Road area, (B) spatial distribution of war activities over the past 2000 years, and (C) human activities versus changes in climate and vegetation. Credit Zhang et al Usage Restrictions None License Original 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.