Input (grade 13): While the western part of the boulevard retained its character, the area around present-day Bebelplatz was integrated into the fortification of Berlin in the aftermath of the Thirty Years' War, visible until today as there are no trees.
Output (grade 6): While the western part of the boulevard retained its character, the area around present-day Bebelplatz was changed after the Thirty Years' War and fortified. There are no trees.