In October 1809, General Wellesley ordered the construction of a series of fortifications and defensive structures that become known as the Lines of Torres Vedras, or simply ‘Linhas de Torres’. Located on the Lisbon peninsula and taking advantage of the morphology of the terrain, these three lines were designed with the purpose of blocking the French army from reaching the capital and, in case of defeat, enabling the British army to withdraw in safety. This system of fortifications was the largest piece of military engineering ever undertaken in Portugal and carried out to a large extent by drawing upon the support of the local population with the greatest of secrecy.