In the morning, I took a long walk through the vineyards in the countryside behind the medieval citadel to look for a good view point. There were no good views of the citadel but some nice views of the vineyards and the white capped Pyrenees Mountains to the south.
Afterwards, I went into the citadel which was already packed with people and walked around the stone walls. There were some nice views of the new part of the city and the Carcassonne Cathedral and the huge tower of the Église Saint-Vincent. The inside of the citadel is barely worth a visit since it seems to always be packed with people.
In the afternoon we took along walk along the scenic Canal du Midi and watched the party boats go by. The canal is 240 km long and goes all the way from Toulouse to the Mediterranean.