The Dutch fortress of Philippine, shown in this eighteenth century map, lay in the central part of a flood zone in Zeeland Flanders in southwestern Netherlands, an area the French invaded three times between 1702 and 1814, occupying it twice. The Dutch prepared an east-west corridor (beginning at the town of Sluis and ending east of the town of Hulst) to be flooded in case of warfare. During France’s campaigns, French Intelligence gathered information, including maps, like this one, preserved in archives at Vincennes. When the Dutch flooded the lands around Philippine in 1747, the area silted up excessively, and French Intelligence knew they only had to wait until low tide for their troops to be able to cross some areas.Credit: Ministère de la Défense (France), Service Historique de la Défense