We bought a 24 hour pass for water bus. On the next day, our water-bus pass still have an hour to go, then we decided to take bus no. 1 for a tour. This is because route no. 1 travels through the grand canal of Venice island, so that we can have a view of the city along the canal.
Hence it is not necessary to pay 80 Euros for gondola, unless you really want to take a ride on gondola.
First picture is Ponte della Costituzione - the bridge linking Venice Island to the train station.
Second one is the Venice train station
Then, Rialto bridge
and we left the waterbus at Piazza San Marco