It dawned a little colder and rainy on the Danube today.  We arrived in Passau after a comfortable night cruising the river.  Several of the group chose to take a bus trip to Salzburg, but I opted for the walking tour of this wonderful river town.  The highlight is the cathedral, home of one of the largest organs in the world.  It used to be the largest, but the Mormon Tabernacle and a church in LA has larger ones.  This particular organ is, in fact, 5 different sets of pipes, three in the back and two in the front, played from a single keyboard station.  The result is that the musician can create a surround sound effect purely by changing which organ that he played.  The summer organ concert series is due to begin next week, and the master organ tuner was busy adjusting each pipe individually.  With more than 1750 pipes, this is a pretty daunting task.  In the afternoon, we set sail for Linz, where we were to pick up the folks on the Salzburg tour at about 7:00pm.  Although still in inclement weather, the river was picturesque and the passage through several sets of locks was fascinating.  In the evening, we were enjoyable entertained by two opera singers who sang Mozart to the Sound of Music.  A wonderful end to our first day into Austria!