Grand blockhaus, Military museum in Batz-sur-Mer, France.

Le Grand Blockhaus is a concrete bunker 25 metres long and up to 17 metres high, with 285 square metres of interior space. Its stepped roofline and pale beige-grey walls bear horizontal seams and a large whitish patch. Blue lettering reading "Le Grand BLOCKHAUS" marks the upper front wall above a recessed glass entrance reached by concrete steps.

This structure was built as a German command post and part of the Atlantic Wall coastal defense system. It remained active until May 1945, when the Saint-Nazaire pocket surrendered.

The rooms display daily soldier life through recreated quarters and communication centers used during the occupation years. You can see how people worked and lived in these confined concrete spaces.

The museum is entered through a glass door at the top of a concrete stair with metal handrails. Inside, twelve reconstructed scenes are arranged over the 285 m² interior, with a video room showing interviews filmed in 1999. A 24-tonne 240 mm gun stands outside.

The top level features a 360-degree viewing platform located about 28 meters above sea level. From there you can survey the entire coastal landscape and understand the strategic location of this site.