It took 27 years for Lorenzo Ghiberto to craft the masterful east doors of Florence's Church of San Giovanni in the 1400s, and it took 27 years in the modern era to restore the gold-coated bronze reliefs to their glory.
The nine-tonne doors, which are five metres tall and three metres wide, were removed after a flood in the 1960s and replaced by a replica. Resoration work, which required lengthy fundraising, began in 1985.
The panels depict scenes from the Old Testament of the Bible and employed techniques of perspective which were novel in the Renaissance.
Claudio Lavanga reports from Florence.