In the autumn of 1502 Leonardo was quartered with Cesare Borgia’s retinue in Imola, 65 miles (100 km) north-east of Florence, where he made this magnificent map of the town. Leonardo paced the lengths of the streets and took bearings from the tower of the central Palazzo Comunale, then constructed the map by geometry. He shows the streets and walls of the town with great accuracy, but does not suggest any improvements to the fortifications.