At the beginning of 1995, United States Fish and Wildlife Services together with Canadian biologists captured 14 wolves in Canada and put them in Yellowstone’s national park, where they have been extinguished since 1926. In the upcoming years, more wolves arrived. The effect was unbelievable. The ecosystem in the national park changed, and it changed so much even the rivers changed. How is this possible? Watch the video and feel astound over the circle of life and our nature.