The painstaking restoration of Venice\'s famed Bridge of Sighs and the facade of the adjoining Doge\'s Palace is finally finished after three years of work, officials said on Thursday. The restoration project -- which was launched after a piece of marble fell off the Palace and hit an elderly German tourist on his leg in 2007 -- included cleaning off pollution and restoring the limestone. Built at the beginning of the 17th century, the small bridge links the palace to a prison, and folklore has it that prisoners crossing to the cooler sighed in despair at seeing the city\'s lagoon for the last time. One of the most famous jailbirds to have crossed over was Latin-lover Casanova, who was arrested in 1755 but managed to escape the confines of the prison 15 months later -- with the help of a monk. The bridge, a hotspot for enamoured couples, has inspired many poets, including Lord Byron who coined the name in his poem \"Childe Harold\'s Pilgrimage\" in which he said: \"I stood in Venice on the Bridge of Sighs.\" Two similar bridges stand in England\'s Cambridge and Oxford universities. The restoration cost 2.8 million euros ($3.7 million), at least half of which was raised through giant billboards draped over the bridge and adjacent building, causing no little controversy in the city of gondolas. \"It is clear that no-one likes to see the city\'s buildings covered up and used for publicity. But if it allows us to save them, no-one can deny it is useful,\" mayor Giorgio Orsoni said before the restoration was finished.