www.jugendheim-gersbach.de

Anchor text: German language article with images on military fortifications

Wikipedia: Fascine knife

Anchor text: Replica of a hexagonal redoubt at 1:1 scale with a link to the construction diary

Wikipedia: Schanze

Anchor text: Illustration of a miner with miner's apron (triangular type)

Wikipedia: Miner's apron

Anchor text: Overview & historical background

Wikipedia: Baroque fortifications in the Black Forest