On November 4, 1966, the Arno flooded parts of the city centre, killing at least 40 and damaging millions of art treasures and rare books. There was no warning from the authorities who knew the flood was coming except a phone call to the jewellers on the Ponte Vecchio. Volunteers from around the world came to help rescue the books and art, and the effort inspired multiple new methods of art conservation. Forty years later, there were still works awaiting restoration.