Each year, on the eve (June 16th) of the feast day of San Ranieri, the city's patron saint, the Pisans light up the buildings along the river Arno with thousands and thousands of lampanini (small glass lamps containing candles). The event is known as the Luminara di San Ranieri.
The salient features of buildings (windows, balconies, cornices etc.) are picked out with narrow strips of wood (painted white and known as biancheria), to which the lampanini are attached.
The lamps are lit in the early evening and, as the light wanes, they slowly become more and more visible, creating a magical effect. When it is completely dark the street lights are switched off leaving the candles as the only form of illumination.
The evening ends with a bang with a display of fireworks.
The tradition of the Luminara di San Ranieri dates back to 1688 when the urn containing the mortal remains of the saint was moved to the Cappella dell' Incoronata in the Duomo, thereafter dedicated to San Ranieri.