So we meet up and go to a submarine. There is a museum and we can take several people to our group. Now idea how detailed this museum is, but come on, have you ever stand inside of a soviet submarine? Then we will take a regular boat to a beautiful river terminal. It takes 20-30 min (10 on water) to the terminal. And then a park, hotdogs, there is a cinema on the park, open under the sky, a fountain, so anyway we will have fun.