On the third weekend of July - this year on the 17th and 18th of the month Venice transforms itself and fills its streets with the cheerfulness attached to the most traditional and popular historic celebration in the city. With a history of more than 450 years, the Festa del Redentore draws scores of visitors to the island of Venice, who come to watch and celebrate this sensational event held to commemorate the historic events of the glorious city of St Mark.Due to its sea and naval supremacy, the Serenissima Republic was at the centre of numerous sea operations and coming and goings from everywhere. This was at the base of the citys wealth and hegemony on the Mediterranean sea. But the continuous trading and commercial activities exposed the city to the risk of infections, diseases and pestilences from foreign countries. For this issue the city had two islands at its entrance called Lazzaretti, where those arriving in Venice would be made to spend time whilst the doctors of the Serenissima carried out health checks on them.Unfortunately, these precautions did not prove enough to protect Venice from three plagues that hit the city over a period of 400 years and caused the population of the whole of Europe to halve. Plagues had always been a serious danger for sea ports where black rats, infested with plague flees, would stealthy abandon the ships and spread the pestilence.Between 1575 and 1577, Venice was hit by an epidemic that wiped out a third its citizens in only two years. In September 1576, when human efforts were appearing to be completely ineffective towards the pestilence, the Venice Senate asked for divine help and made a vow to build a new church and dedicate it to the Redeemer. In May of the following year the first stone of the Andrea Palladios project was laid. Within a short time, on 20 July, the end of the plague was celebrated and a tradition that is still followed to the present day started. On the Saturday preceding the third Sunday of July a long bridge of ships is put together, over the Giudecca Canal, so that this island is linked up with the shores of the Zattere at the location of the Church of the Holy Spirit. The ensued foot procession can therefore carry on to the Church of the Redeemer where mass is celebrated by the Patriarch of Venice.The commemoration is not just a religious one, thousands of people spend the evening of Saturday on their boats, adorned for the occasion, or on the shores of St Marks dock and hang around together until 23.30 when, as it is tradition, fireworks are let off, which are year after year increasingly more spectacular and colourful. The fireworks turn the lagoon city into a unique stage, where the play of light and reflex draw a kaleidoscope of colours in the skies behind the spires, the domes and the bell towers of the city and instil unique emotions in all those visiting the lagoon at this time of the year.