When I wrote my novel Eu, do Nada (I, From Nothing) I was inspired by the story of my maternal family. Chapter II is all about the French Invasions of 1807-1810 and how my ancestors sought refuge in the forts built by the Portuguese and their English allies.
Now a tourist site (and a place of frolicking for one Tesla-wife), the forts were meant to thwart the Armies of Napoleon and shelter the locals. Built on the crest of the hills around Lisbon, they combined to make the defense lines of the Portuguese capital.
Starting in the now town of Torres Vedras, some 50kms north of Lisbon, they got the name of Torres Lines (Linhas de Torres) and proved their worth by being invencible bulwarks against the invading hordes.
Of course, the roads leading to the forts are no pavement fit for a Tesla Model S. Still, made for carts and canons, they withstood the tests of time (neglect and forgetfulness) and can now by fully appreciated whilst behind the wheel of a super-future-forward electric car.