THE UMBRIAN REGION is famous for the religious art in the churches and abbeys of its numerous medieval cities, masterworks from the thirteenth and fourteenth centuries - especially those created by the Vatican painter Pietro Perugino, who took his name from the region's largest city, Perugia. Those paintings served as Scripture in the ages before common people knew how to read, and they especially depict the rich Catholic history of Umbria. Many of the region's ornate churches are dedicated to the gentle Saint Francis of Assisi, because he traveled all over Umbria working miracles and preaching to the people.

But Nini's find was a former Benedictine abbey, clearly more of an archaeological attraction than a tourist mecca or a religious shrine. Once upon a time, the abbey was accessible through the Benedictine convent above it. But the convent had been abandoned for more than a century before eventually being destroyed during World War II. The entrance to the long-forgotten underground chambers was obliterated - and then a hole opened up in an old man's garden in 1979.

Up until that time, Nini had been an apprentice surveyor. But after his discovery, he followed his fortune and pursued a doctorate in archaeology. For the last 26 years, subterranean Narni has been his life. Working with paintbrushes and dental utensils, he and a volunteer staff have peeled away layers of history. They have uncovered a 2,000-year-old Roman cistern, the remains of what appears to be a house, and even the tusk of a woolly mammoth.

Today the hidden rooms are referred to as Narni Sotterranea, or "Narni Underground"; you can tour them if you make reservations in advance. The chapel's fading frescoes speak to the passage of time. The torture chamber's walls are hung with photographs of the equipment that would have been used there during the Roman Inquisition, which lasted until the 1830s. The graffiti left by the prisoners is intact.