The anti-tank ditches near Ukraine's occupied southeastern town of Polohy stretch for 30 km (19 miles). Behind are rows of concrete "dragon's teeth" barricades. Further back are defensive trenches where Russia's troops will be positioned.
The defences 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.
