The anti-tank ditches near Ukraine's occupied southeastern town of Polohy stretch for 30 kilometers. Behind are rows of concrete "dragon's teeth" barricades. Further back are defensive trenches where Russia's troops will be positioned.
The defenses visible in satellite imagery taken by Capella Space are part of a vast network of Russian fortifications sweeping down from western Russia through eastern Ukraine and on to Crimea built in readiness for a major Ukrainian attack.
Thousands of Ukrainian troops have been training in the West to use different military assets on the battlefield in a combined way ahead of a counteroffensive Ukrainian officials say will come when its forces are ready.