Entrance to the Bunker System (IMAGE) Pensoft Publishers Caption This is a partly blocked entrance to the bunker system. In the background, pine-spruce forest overgrowing the hillock built to camouflage the structure. Credit Wojciech Stephan Usage Restrictions CC-BY 4.0 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.