Usually held on the last Sunday of October, the October Maratona (Marathon) is held annually. It starts at Villa Pisani on the mainland and ends along the Zattere for a finish at the Basilica di Santa Maria della Salute on the tip of Dorsoduro. 

More Festivals in Venice
Ascension Day of Festa della Sensa
Madonna della Salute
Palio of the Ancient Maritime Republics
Regata Storica