For seven centuries, Savoy and its Alps were an independent state between France and Italy. Its rulers controlled the passage of armies, merchants and pilgrims over the mountain passes. Annexed to France in 1860, Savoy became its most prosperous region with fifteen million tourists visiting its Alps every year, to walk, climb, parapente or ski. Savoy and its Alps were for seven centuries an independent state at the centre of Europe, separating France from the patchwork of principalities that made up Italy. Merchants, clerics, pilgrims, diplomats as well as privileged young Englishmen on the Grand Tour, regularly used the Alpine passes. But it was the need of European armies to cross Savoy which made its rulers powerful as the Gatekeepers of the Alps. It allowed the Duchy of Savoy to prosper and survive when all the other great duchies of Burgundy, Milan, Provence and Dauphine disappeared at the end of the fifteenth century. Savoy successfully resisted the pressure from Protestant Geneva on its doorstep, but was the first country to succumb to the French Revolution. By judiciously switching alliances during the European wars beginning at the end of the seventeenth century, the House of Savoy finally gained a crown. The conspiracy concocted by Napoleon III and Cavour led directly to the unification of Italy and the definitive annexation of Savoy to France in 1860. Simultaneously, the Alps that had been the source of Savoy's power, now became the source of its prosperity as a centre of tourism.