FOR ALL THE ANCIENT Italian hill towns and villages that delight the traveler — the San Gimignanos, Montepulcianos and Fiesoles — there are scores of others (many equally or more beautiful) where few venture and in which very few reside today. According to a 2016 Italian environmental association report, there are nearly 2,500 rural Italian villages that are perilously depopulated, some semi-abandoned and others virtual ghost towns. A primary narrative of Italy in the 20th century has been what followed the collision of poverty, urbanization, mass emigration and natural disaster, a confluence of events that has devastated many towns that had otherwise managed to thrive, or at least get by, for centuries. These towns, most of which are in the historically impoverished south, had already lost tens of millions of inhabitants in the great waves of migration from the late 19th century to the mid 1970s; in the last 25 years, they lost another 15 percent. Now, houses and schools sit empty and fields fallow; shops are unattended.