Brialmont designed the inner line of forts before the introduction of the rifled artillery. The ditch of all forts had to be protected by a total of three caponiers and a escarp gallery. But after 1859 this gallery proved to be too vulnerable and expensive, so it was dropped from the designs. However the construction of Fort 3 had already been started, so its escarp gallery was finished. It is one of the most beautiful masonry constructions. For more informations and photos www.fortenantwerpen.be.