It is one of the most well-preserved and longest defensive walls in Switzerland, built in 1386. The existing wall is more than 900 meters, with nine watchtowers of different styles. Now only four of them are open for visitors to visit outside the winter season. We climbed the highest tower. The Bell Tower is free of tickets and unattended. It depends on tourists'consciousness. The old clock was completely exposed to machinery. The old stairs have been walking for hundreds of years. The clock built by Hans Luter on the Zyt Tower in 1535 is the oldest clock in the city of Ryusen and has the privilege of telling the time one minute ahead of the rest of the city. Standing on the wall, you can overlook the whole Ryusen. The lake view and the mountains in the distance are intoxicating.