I was surprised to find that many museums and galleries and restaurants in Vienna are closed on Mondays. Others are open Wednesday through Sunday and closed on Monday and Tuesday. We had planned to spend 3 days in Pargue, travel one day to Vienna, spend 3 days in Vienna, and then continue our travels.
As it worked out we traveled on a Sunday and arrived late in the afternoon at our hotel in Vienna. More than half the places we wanted to see are closed on Monday and we planned to leave on Wednesday morning to go to Salzburg. We were able to work around the problem but it meant more travel around the city as we could not cluster destinations with half open only on Monday and the other half open only on Tuesday during our visit.