Venice is a beautiful floating city full of culture.
However, it is difficult to access this culture in such a tourist orientated city.
The first thing you want to look at is the modern art gallery, The Peggy Guggenheim Collection. This is an easy waterbus trip to Academia (make sure you get a couple of days pass to avoid the steep €7.50 per trip). There you can spend time in the garden with neon art works and sculptures, as well as appreciating classic names such as Picasso and Jackson Pollark.