(CNN) The war in Ukraine will soon be three months old. And the natural boundaries shaped by one river in eastern Ukraine are already affecting the progress of each side. The river starts in Russia and flows into Ukraine , forming swamps, floodplains and oxbow lakes, cutting through chalk cliffs as it goes. In the last month, since occupying Izium, they have made only limited progress despite the stretched Ukrainian lines. To sustain an offensive in this area, the Russian military needs supplies, and they must come from across the border.

Source: CNN May 13, 2022 07:51 UTC