This image was acquired from
wikimedia. It was marked as Public Domain or CC0 and is free to use. To verify, go to the source and check the information there.
Keywords from Image Description:
Fotothek df tg Festungsbau Bastion Schanze Redan Ravelin Schanzkorb Approche Batt. Scan Deutsche Fotothek dftg color MIKCenter Berlin GmbH Abbildung VVVV Amsterdam Ansichten von Befestigungsanlagen Schanzkrbe Blendungen Approchen Papier Kupferstich cm Festungsbau Bastion Schanze Redan Ravelin Schanzkorb Approche Batterie