Why Vienna? Why three weeks?

Usually if you go through travel books you will find the headings 'If you have three days..., If you have five days...'  and almost everyone agrees that five days is more than enough time to 'see' Vienna.   So why are Alan (my husband) and I spending three weeks here?  Alan has been working on a writing project for the last couple of years.  He seldom has time to do much writing during the school year, so at the end of the spring semester he reviews whats he's done and begins in earnest.  Then, inevitably, he turns his attention to our summer travels.  this not only takes time away from his writing, but the flow is interrupted by our 3-4 weeks away.  By the time we return he only has a few weeks before he must turn his attention to preparing for the upcoming semester.  (No, not all college professors waltz into the classroom and spew off the top of their heads - as a matter of fact most don't.) So this year we decided three weeks in one city to cut down on research and to make it a 'working vacation' with Alan spending his mornings writing