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Keywords from Image Description:
ValkenburgPlenkertstraat mijnbouwSchacht . en Shaft in rock with mining traces Valkenburg Limburg the Netherlands nl Schacht in rotswand met sporen vuursteenmijnbouw Plenkertstraat Limburg Nederland own Romaine zoom type landmarkregion NL Cczero Neolithic flint mines of Valkenburg Caves in the Netherlands Cretaceous geology