Situated on the banks and by the outlet of the river Arno, it had been one important Republic of the Sea and spreaded its power out to Corsica isle. Its artistic estate is mostly in Miracles' Square where you can admire the Cathedral, the baptistery and especially the bell tower, known all over the world as the "Leaning Tower". Another important monument is the Church St. Maria della Spina, recently restored, on the Arno's riverside. The magic of the Luminara di San Ranieri is rekindled at dusk on 16 June along Pisa’s Lungarni, the river Arno. This remarkable illumination custom is traditionally performed by Pisans to celebrate annual festival for the Patron Saint the following day. In honour of the patron saint of Pisa, San Ranieri, on 17 June four vessels representing the four ancient districts of the city take to the Arno to compete in a regatta in commemoration of the Pisan maritime tradition.