There are six of us ages 10-70 and we have two full days in July (a Monday and Tuesday). I'm not sure what we can get done in one day or what goes well together. I also know the secret tour may be booked already. Here are the things I think I'd like to do: St. Mark's Square, St. Mark's Basilica, clock tower (is this Campanile di San Marco?), Doge's Palace - Secret tour (Palazzo Ducale), gondola, ride on the Grand Canal, Murano, Burano, Rialto Market, mask painting (15 year old wants to do this).