The “Ghirlanda” or Garland, was an outer wall, completed with two round defensive towers and a covered road, which protected the northern side of the castle of Porta Giovia, running from from the south-western ravelin of Santo Spirito to the ravelin of Santa Maria del Carmine in the north-east. Already in use at the time of the Viscontis, the fortification was repaired and extended to the round towers by Francesco Sforza. A sketch by Leonardo, dated between 1487 and 1490, that can be found in manuscript B (Paris, Insitut de France) carries a section of the Ghirlanda and the north-west corner of the castle inclusive of all the measurements of the fortress. In 1893 the entire defensive complex of the Ghirlanda was heavy-handedly demolished. Today, all that remains of the Ghirlanda in the park are a scattering of ruins, corresponding to the round corner towers and the Porta del Soccorso entrance.