View looking back south at the Frederick gate; A national historic site and the location of a partial reconstruction of an 18th century French fortress at Louisbourg, Nova Scotia, a reminder of imperial battles for what would become Canada. The original fortress, constructed mainly between 1720 and 1740, was one of the most extensive (and expensive) European fortifications constructed in North America. Fortress Louisbourg suffered key weaknesses, since its design was directed solely toward sea-based assaults (controlling the entrance to the Gulf of St Lawrence and the St Lawrence River), leaving the land-facing defenses relatively weak. Captured by British colonists in 1745, it was a major bargaining chip in the negotiations leading to the ...