You are standing at the base of the largest alpine fortification in Europe, a place often whispered about as the Great Wall of the Alps. Stretching for more than three kilometers across the rugged mountainside of the Chisone Valley, the Fenestrelle Fort covers an astonishing one point three million square meters. It is not just one building, but a massive chain of three major forts and multiple redoubts linked by miles of stone walls. Built by the House of Savoy between seventeen twenty-eight and eighteen fifty, this structure was designed to be an impenetrable shield for the city of Turin against French invasion. As you look up towards the peaks, you are witnessing an engineering feat that took one hundred and twenty-two years to complete.