For two days, oxygen-starved Russian troops crawled nine miles through a pitch-black underground pipeline, creeping behind enemy lines and springing a surprise attack that wiped out the enemy in a blaze of bullets.
The Ukrainian soldiers had no idea that Operation Potok was coming.
Hundreds of men streamed out of the pipeline, storming Ukrainian positions north of Sudzha, pushing them back out of Russia in a triumphant counter-offensive to save the motherland.
