The Forte di Marina was built along the Bibbona coast by the Lorena family as part of an effort to rienforce the military organization of the Tuscan Granduchy. It was built in the second half of the 18th century, at the same time as the Forte di Castagneto, and completed at the end of the 1700s. The fort offers coastal protection, sanitary control, efforts against smuggling activity and a point-of-reference for naval mercantile activity. The fort's square form has a brick facade and an open terrace which would have once supported a line of cannons. The interior offered space for the guard corps who used it as a base for their patrols.