On the hike, you will pass various nature conservation measures of the Life+ project "Rur & Kall - Habitats in the river", the Düren Biological Stations and the StädteRegion Aachen. The construction measures promote the continuity of the Kall and improve the habitat of migratory stream inhabitants such as brown trout, bullhead and small creatures at the bottom of the river.

As early as 1512, there was a water-powered mill on the site of today's Zerkall paper mill not far from the starting point of the tour, which over the course of time served as a grinding, fulling and oil mill. Today, the Zerkall paper mill's handmade paper is known all over the world and was used to print the German constitution in 1949. With a bit of luck, you can spot kingfishers at the paper mill. If you take a closer look, you may spot other animals, such as the common lizard sunning itself on a fallen tree trunk or the dipper, the only songbird that can dive underwater for up to 30 seconds in search of food.

A wooden bridge leads over the Kall, where the floodplain opens up to reveal extensive meadows. Shortly before Zweifallshammer, the Kall can be crossed via a ford. The problem is that unpaved roads cause more sediment to enter the watercourse. For this reason, the access roads are reinforced with stones. Beaver gnaw marks are also clearly visible here. The Kall is a challenge for landscape designers. During heavy rain or floods, the current is so strong that it repeatedly destroys dams. The small side streams of the Kall, such as the Tiefenbach, are better suited as habitats.