Azovstal has clearly become a symbol of Ukraine’s fierce defense against Russia.
What makes it special is the underground fortress in this steel plant, and the focus of attention as it is the last holdout in the strategic port city. The steel plant has been largely reduced to rubble amid Russian bombardment. The plant’s tunnel network has sheltered Ukrainian defenders and has become a story of heroism for the country.
Azovstal is one of the largest metallurgical plants in the world, located east of the port city of Mariupol. This factory was built in 1930 with almost full support and funding of the Soviet Union. In 1933, Azovstal’s first metallurgical line came into operation. This was considered a “gift” of the Soviet Union to Ukraine.
Thousands of workers from all over Ukraine then flocked to Mariupol to work, with the goal of turning Azovstal into one of the world’s leading metallurgical centers. Not only the factory, the seaport in Mariupol was also built so that cargo ships could easily reach Azovstal.

Azovstal covers an area of about 11 square kilometers with many buildings, smelters, and a “maze” of roads and underground tunnels. The Azovstal plant was designed by Soviet engineers to be able to ensure production even in wartime conditions.
Specifically, under Azovstal there are 6 underground works, about 24 km long, built of reinforced concrete. These tunnels were designed in a rather complicated way, with a ceiling of reinforced concrete 8 meters thick, enough to withstand a tactical nuclear bomb attack. Power supply, water, drainage, underground cables… of Azovstal factory are arranged in these tunnels. The tunnels in Azovstal are said to connect to each other, but not to a neighboring city, according to the Guardian.
Azovstal became the last stronghold of Ukrainian forces defending the port city of Mariupol. The system of solid tunnels crisscrossed inside the factory creates ideal hiding and moving conditions for the thousands of Ukrainian servicemen in Mariupol, and about 1,000 civilians trapped in the area since Russia surrounded the city.
The 90-year-old metallurgical steel plant was almost completely destroyed by Russian forces during the siege of Mariupol and has been surrounded by Russian troops since early March. The entire city has had limited access to food and water throughout the blockade and bombardment. The factory has since emerged as the last pocket of organized resistance in the siege.