Russian siege of Avdiivka started in October 2023 and was largely stuck on frontal attacks until 20 January 2024 when Russian soldiers suddenly emerged behind the Ukrainian advanced defense positions in "Tsarska Okhota". This video is an excerpt from a longer 50 minutes film by Russian reporter Sladkov which documents the details of this operation. The excerpt focuses on the technical aspects of the breach and skips most of Sladkov babbling. Main points of the video:

• In Avdiivka, there were two drainage systems - old tunnels, partly above ground and partly underground, and new pipes on the surface
• The new pipes were mapped, Ukrainian forces knew about them and disrupted them with artillery
• the old tunnels were not on the current maps
• the preparation took two months
• the first group of divers had to walk/swim 3.5 km to the end of the tunnel, to confirm whether it was feasible at all
• the first passage took 4 days non-stop, with underground camping
• in the tunnel, several sections were flooded almost to the ceiling, leaving ~15 cm of space
• this was probably due to the fact that the pipes/tunnels were not completely horizontal
• some sections were also silted up so that you had to go on all fours
• there were fish in the water, including catfish
• Then they started pumping out the water from the whole tunnel using a cascade of pumps
• The pumps and the water outlet were camouflaged (successfully, as you we see)
• The tunnel had very strong acoustics, so movements inside were either ‘on tiptoe’ or drowned out by Russian artillery
• In some sections, there was very poor ventilation, so the Russians took oxygen with them even after the tunnel had been dried out - not full oxygen apparatus, but small cylinders to improve their breathing
• The distance in the tunnel was measured with a surveyor's wheel.
• The tunnel walls were cut with a gas torch.
• A total of 450 soldiers and a huge amount of ammunition were gathered just before the assault on the tunnel - the tunnel was practically turned into a bunker
• While one group fought on the surface, the other rested in the tunnel, the groups did not return 3.5 km to the entrance
• There were a total of 13 (!) exits from the tunnel in different places, and they all attacked at the same time
• The tunnel did not go under the Avdiivka but to the west of it, but still behind the ZSU positions
• In one position, the tunnel went right under Ukrainian trench - the trench was deep enough to reach the metal pipe of the tunnel and Russians moving inside could hear chatter above