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Fotothek df tg Geometrie Architektur Festungsbau Bollwerk Kurtine Ravelin. Scan Deutsche Fotothek dftg color MIKCenter Berlin GmbH Abbildung Nr Nrnberg Verschiedene Grundrisse von Festungsauenwerken Ravelin Kurtine Tenaille Horn und Kronwerke Papier Kupferstich cm Geometrie Architektur Festungsbau Bollwerk Kurtine Ravelin