While walking through xerothermic grasslands in Owczary one can come across mysterious ditches stretching around the tops of the hills. These are trenches, or remnants of military fortifications from World War II, in the shape of a broken lines. During the war they were quite deep, used for the attack and movement of soldiers, as well as for protection against attack and, on top of the hills, as a good observation point.
Currently, the trenches are already shallow, but still well visible, the easiest way to observe their size is on aerial and satellite photographs (e.g. in google maps, geoportal).