The third fort on this site, Fort Chambly, began construction in 1709. It was made of stone and assumed a somewhat castle-like appearance rather than the low-lying bastioned fortresses of Europe. It was built in such a way as to make it impressive and all but impregnable to Indian enemies and colonial American raiders. Its wall facing the Richelieu River was pierced for artillery. During the War of 1812, it was the HQ for a large contingent of British and Canadian troops guarding the area south of Montreal against an advance by American armies. The fort later fell into ruins during the 19th century. Recognized as a unique surviving example of military architecture, Fort Chambly had a major volumetric restoration in the 1980s by Parks Canada giving it back its appearance in the middle of the 18th century.