The CPIE (Centre Permanent d’Initiatives pour l’Environnement Val de Vilaine) is organizing a nature outing on Thursday, February 19, 2026, at 2:30 PM, focusing on the alignments of the mill and the Bû castle, known as the megaliths of Saint-Just. This free or low-cost activity is part of the 2026 nature animation program offered by the Department of Ille-et-Vilaine and its partners, aiming to showcase the natural heritage of the region. Registration is mandatory and closes the day before at 5 PM, with limited spots available.