Photo de stock - 25 May 2023, Brandenburg, Greiffenberg: Ingo Waligora, a certified hobby windmiller and member of the Association for the Promotion of Agriculture, Crafts and Culture, turns the blades of the octagonal earthen holland mill toward the wind. On Whit Monday (May 29, 2023), 713 historic mills nationwide will open their doors, let the blades or water wheels turn, rev up engines, run transmissions and invite guests to guided tours and small festivities. The occasion is the 30th German Mill Day, which the German Society for Mill Research and Preservation (DGM) and its state and regional associations have traditionally organized on Whit Monday since 1994. The octagonal earthen holland mill is also open to visitors then. The 15-meter-high mill, built in 1830, was in operation until the 1930s and then again for a few years after World War II. Since its shutdown, the historic windmill fell into disrepair during GDR times. Since 2006, the Greiffenberg Windmill Association has been working on its reconstruction. According to the association, more than one million euros have been invested from donations. Last summer, new blades had made the mill with its characteristic rotating cap complete again. Photo: Patrick Pleul/dpa. - Greiffenberg/Brandenburg/Germany