Florence is a city of secrets. As you walk through the ancient streets, large wooden doors open, revealing monastic courtyards, previously unknown workshops, and fresco-filled entranceways. There’s always something new to discover. On a sunny spring afternoon, therefore, I shouldn’t have been surprised to stumble across a hidden courtyard filled with tropical plants and sprawling vines set against sun-baked ocher walls, leading me to the oldest silk factory in Europe. Unassuming doors open to a large space with sunlight pouring in from skylights high above, diffused by canopies that protect the delicate silk production below. The room is filled with machines, wooden structures, and complicated mechanisms singing a repetitive melody that echoes throughout. Antico Setificio Fiorentino (ASF) is the best-kept secret in Florence, and still uses weaving machines that were built prior to the 19th century—one designed by the maestro Leonardo da Vinci. Silk production was introduced to Italy sometime …