Siena is a fairly small city and we were able to visit most of the major sights in one day.  We started by heading to the very impressive Siena Cathedral, which is huge for a city as small as Siena.  After visiting the cathedral-related sights, we walked to Il Campo (the main square) where we picked up food and strolled for a while before heading back to the hotel.  We took a taxi back to the train station and then headed for Rome, our last stop on the self-guided portion of our honeymoon.