The flood of November 4, 1966 damaged thousands of works of art and drowned close to a million books at the National Library alone, and countless archival documents in a matter of hours. The water itself was only part of the problem. It carried mud, sewage and heating oil from thousands of basement tanks, and that mixture soaked into paper, canvas, wood panel, plaster and stone. What followed was the largest emergency conservation effort ever attempted, and the methods worked out in Florence over the following years shaped how museums, libraries and archives everywhere treat damaged collections today.

The first weeks

Triage began before the streets were clear. Panel paintings, the most vulnerable works of all - wet wood swells and warps, and the paint and gesso on top of it lift away - were taken to the Limonaia, the great lemon house of the Boboli Gardens, where the temperature and humidity could be brought down slowly so the panels would not crack as they dried. Paintings were faced with tissue paper to hold flaking paint in place. Umberto Baldini, director of the conservation studios of the Uffizi, led much of the work on paintings, alongside scientists such as the University of Florence chemist Enzo Ferroni, whose collaboration with restorers became one of the flood's lasting legacies: the partnership of conservation and science.

Cimabue's Crucifix

No single object came to stand for the flood more than the great painted Crucifix by Cimabue in the Basilica of Santa Croce, made before 1288 and one of the founding works of Italian painting. In 1966 it was displayed in the museum of Santa Croce, at ground level, and it was completely submerged. When the water fell, much of its painted surface had come away - estimates of the loss run from about 60 to 80 percent - and the photographs of the ruined Christ went around the world.

The Crucifix went first to the Limonaia and then to the restoration laboratory set up in the Fortezza da Basso, where it underwent a long and, for its time, innovative restoration. The restorers chose not to repaint what was lost. The missing areas were filled with a neutral, finely hatched technique that reads as a quiet tone from a distance and shows clearly what is original up close - an approach that became a reference point for conservation ethics. The Crucifix returned to Santa Croce, and since 2013 it has hung in the basilica's sacristy, on a mounting that allows it to be raised out of reach of floodwater.

Vasari's Last Supper

The flood also struck Giorgio Vasari's Last Supper of 1546, a huge painting on wooden panels that hung in Santa Croce's complex. It spent many hours under water, and for decades it was considered beyond saving: the panels were stabilized and put into storage, too damaged and too fragile for anyone to attempt more. The restoration was finally carried out by the Opificio delle Pietre Dure, using techniques and materials that did not exist in 1966, and the painting returned to Santa Croce in November 2016, for the 50th anniversary - half a century after the flood.

The National Library

The Biblioteca Nazionale Centrale di Firenze, one of Italy's two national central libraries, stands on the Arno at Piazza dei Cavalleggeri, between the river and Santa Croce. Much of its collection had been stored in the basement since 1944, and when the embankment wall in front of the library gave way on the morning of November 4, close to a million volumes were inundated, among them newspapers, periodicals and early printed books from the historic Magliabechi and Palatine collections.

The rescue of the library's books - first by volunteers in human chains, then by teams of conservators led on the technical side by the English bookbinder Peter Waters - is told on our page on the mud angels. It produced the methods of mass treatment that are now standard in library disaster response. And the job is not over. Sixty years later the library is still restoring flood-damaged books; for the 2026 anniversary it involved students and citizens in a project to recover some 30,000 volumes that had never returned to use. One surprise of that long work: the destruction of old bindings revealed manuscript fragments that had been hidden inside them for centuries.

The archives

Less famous than the paintings, but at least as badly hit, were the city's archives. The Archivio di Stato di Firenze, then housed in the Uffizi, saw roughly 40 percent of its holdings damaged The Archivio di Stato di Firenze, then housed in the Uffizi, lost and damaged vast quantities of recordsmdash; property and tax records, registers of births, marriages and deaths, court and police files, and the work of recovering, restoring and reordering them has continued for decades. The State Archive's 2026 exhibition, RI-EMERGERE 1966-2026, presents the results.

What the flood changed

Before 1966, restoration was largely a craft practiced object by object, according to the traditions of individual workshops. The flood confronted the field with damage on an industrial scale, all at once, and with a stream of foreign specialists who brought their own methods. The result was a new kind of practice: systematic documentation, triage according to risk, close collaboration with scientists, international exchange - and, eventually, the expectation that institutions plan for disasters before they happen. Florence's restoration laboratories, unified in the Opificio delle Pietre Dure, became one of the world's leading centers of conservation research and training.

For deeper reading, see Books, in particular Conservation Legacies of the Florence Flood of 1966 and Waters Rising.