Today we leave the Danube and enter the Main Danube Canal linking the North Sea to the Black Sea. So far we have been going up the locks, but today we reach the highest point in the trip...406 metres above North Sea level....then we start going down the locks....47 more locks to go....first lock we go down 24.7 metres! The canal was built 3 times...first time too hard and abandoned......second time it was very narrow and got buried with mud the first sign of heavy rain....by this time the railway had come in and was very competitive....however the tried a third time...they used bitumen to harden the bottom, rocks to line the sides and all 47 locks had retaining tanks...no need of pumps....when you go through a lock 60% stays in retaining tanks and only 40% is released. We still cannot go on upper deck....in fact not till we get to Rhine river which is after canal and main river. We did a walking tour of Nuremberg today. Lovely city...Fred chose to stay on ship and I took tour and bought him a tshirt. We saw city museum, imperial castle, main square and beautiful fountain, old town hall, our lady's church, st Lawrence church and the toy museum....then a bit of time for tourist shopping and walking the cobblestone streets. We had dinner in the fancy restaurant again...very nice....then heard a famous franconian vocalist Valerie May entertain us....excellent!