Take the following as truth: For Louis XIV's wars against the Netherlands in the 17th century, the military architect Vauban built a line of fortifications at Calais, Dunkerque, Douai, Valenciennes, and ' still visible ' the great citadel at Lille.
Then the following statement: "The fortifications in Calais were built in the 18th century." is true, false, or inconclusive?