Background
Through the official japanese site I discovered that the place where
Princess Tutu' story happens (Kinkan Town) is real. After some research through
German town's sites I found the exact town in which Kinkan town is based.
The name of that town is Nördlingen.

Nördlingen is an interesting town lying not too far northwest of Munich. The old town is
nearly a perfect circle, with a church (St. George's) in
the center with a tall bell tower.
Nördlingen marks the middle of the Romantische Strasse (Romantic Road),
the oldest
and most popular of Germany’s tourist roads.
It's located between Dinkelsbühl and Donauwöhrt at the Danube.
The original town walls which circle the town are complete and can be walked all
the way around. Also all of its watch-towers are still in place since Medieval
Times.
It also lies in a very interesting area. 15 million years ago, the Ries (About 25 km in diameter)
was formed by the impact of a large meteorite that hit the earth at aspeed of at least 70.000 km/h.
Today this crater is one of the best preserved uns researched meteorite craters in the world.
Similarities between Nördlingen & Kinkan Town