This is the Ultimate Weapon of Trench Warfare

The Russian forces, in preparation for a potential Ukrainian counteroffensive, have also constructed extensive new trench networks, fortified with minefields in areas along the front line that they consider vulnerable. On the opposite side of No Man’s Land, the Ukrainian forces have been strengthening their defensive positions by excavating trenches just behind the front line. In brief, while the front line extends for more than 600 miles, both opposing forces have constructed an extensive network of trenches spanning thousands of miles. These trenches are arranged in successive layers, ensuring that if one network is compromised, soldiers can retreat to safer positions.