When the town was annexed by France in 1678, Vauban made some radical modifications to the defences. He demolished the citadel, deeming it inappropriate as it was not situated on high ground, and built a hornwork in its place. In addition to strengthening the town's defences in many places, Vauban made sluices for inundations protecting the town. The order was given to demolish the fortifications in the late 19th century, but the work was carried out half-heartedly and roughly half of the fortifications were never demolished, remaining to this day. The surviving section of fortifications includes the Menin Gate, a massive monument to the fallen soldiers of the Great War, built on the site of Vauban's original gate (which was called the Antwerp Gate at the time).
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