When gunpowder made high walls useless, Italian architects reinvented fortification, and Francesco di Giorgio Martini was among the most inventive of them. The Rocca of Mondavio, built for the della Rovere in the hills of the Marche, is one of the clearest surviving demonstrations of his thinking: low, thick, sloping masses of brick designed to absorb cannon fire, a polygonal keep, ditches, and internal galleries from which defenders could sweep the approaches. Because it was never attacked, the building has come down to us almost unaltered — a rare thing among military works, which are usually rebuilt after every siege. Inside, rooms devoted to the arms and daily life of the period explain the machine's workings. Filmed in 4K with aerial photography that reveals the geometry of the plan, the programme presents the Rocca as a key document in the history of European military engineering.
