Beneath the pine and beech forests of Wolin Island in northwestern Poland lies a vast underground bunker complex that once served as a top-secret Nazi coastal fortress and later a Cold War nuclear command center. Known today as the Wolin Underground City, the site was originally called Battery Vineta and was built by Nazi Germany starting in 1936. It is now open to the public for guided tours.
The island sits near Świnoujście, a seaside resort town on the Baltic coast, known for its long dunes and largely undisturbed nature. Its sandy ground hides what was once an ultra-secret bunker city.
Nazi origins
Kacper Stachula, who was born and raised in Świnoujście and now leads regular guided tours of the site, said the Nazi command decided in the 1930s to build two coastal defense batteries, named Goeben and Vineta, constructed between 1936 and 1939 in preparation for the Second World War.
The project included a network of bunkers: four topped with rotating cannons, plus another built for command, ammunition and utilities.
The construction defied the 1919 Treaty of Versailles, which had banned German rearmament after the First World War. The area, now part of the West Pomeranian Voivodeship, belonged to Germany before the Second World War, and Adolf Hitler wanted a solid coastal defense in place before launching a war.
The complex never saw major combat. Stachula said that while the front lines of the Second World War advanced rapidly elsewhere, the area stayed calm, and the Nazis eventually converted the whole complex into a naval school. The Soviet Red Army captured the bunkers in 1945.
Although German forces blew up their munitions and tried to destroy the complex during their retreat in May 1945, they failed, and much of it survived intact.
Toward the Cold War
Stachula said no one knew what to do with the site after the war. Soviet troops stripped most of the metal parts and valuables, while local residents looted the rest. It was not until the 1950s that Poland's socialist government decided to turn it into an emergency command center, in Stachula's words, "in case of a Third World War." The site underwent major modernizations in 1955 and again in 1965.
Poland wanted to reinforce its defenses because of an ultra-secret plan to invade Denmark after the signing of the Warsaw Pact in 1955. In what was nicknamed the "Polish front," the existing Nazi bunker infrastructure, remote and hidden among forests and dunes, was seen as ideal for a command post that could shelter the Polish and Soviet military elite if the invasion plan were ever carried out.
The original bunkers had been separate structures. According to Stachula, the Polish army began connecting the five Nazi-era bunkers, building additional tunnels and installing utility bunkers and underground water pumps.
The finished complex included nearly a mile and a half of tunnels. Its perimeter was split into five security zones, each requiring a special document for entry, and it grew into a functioning underground city where soldiers spent months at a time.
Going underground
Visitors today step straight into a Cold War atmosphere. A Soviet-era armored personnel carrier sits parked near the ticket area, fragments of missile fuselage lie scattered among the beech trees, and a heavy Soviet military ZIL truck is parked nearby.
The Wolin Underground City is a privately run museum, so tours work in an unconventional way. Because the complex is so large, visitors can only enter with a guide and are grouped into "platoons," while the guides play the part of strict Polish army commanders, complete with lining up, sharp orders and occasional shouting.
Inside the first bunker, the temperature stays around 10 degrees Celsius, or about 50 degrees Fahrenheit, year-round regardless of conditions above ground.
Unlike many abandoned military sites that feel decayed and sinister, the bunkers remain notably habitable, with original equipment still in place, including telephone exchanges, old radio stations, telecom wiring racks and radar screens that still glow green.
The tour passes through austere barracks with bunk beds and communication rooms where mannequins now stand in for operators at the analog telecom equipment, decoding stations, teletype machines and 1970s-era phone exchanges. The complex also has a separate underground kitchen, an infirmary, a dining hall, a water supply room and a machine room housing a large diesel engine.
The tour reaches its climax in the War Room, the command center where the course of European history could have been rewritten. Original tactical maps made of plexiglass, tables with old computers and an imposing red telephone remain exactly as they were the last time the military used the site.
It was from this room that Polish general and later military dictator Wojciech Jaruzelski, along with Soviet commanders, worked out plans for a nuclear strike on Scandinavia and, eventually, the rest of Europe at the height of the Cold War.
Stachula said the plan called for deploying tactical nuclear warheads at ports in Denmark and West Germany to break through NATO defenses before pushing ahead with a larger offensive.
Had the plan been carried out, a large-scale nuclear war could have broken out in Europe. The red telephone was never used to give that order.
Hidden in beauty
The Wolin Underground City is growing in popularity, currently drawing about 3,000 visitors a month, according to the Polish Tourism Organization, but parts of it remain a mystery. When German forces retreated in 1945, they sealed some tunnels behind thick concrete walls, and stretches of the underground complex have still never been explored. As with Project Riese, another vast underground Nazi complex in Poland's Lower Silesia region whose true purpose remains unknown, the undiscovered passages could still hold objects, and possibly stolen valuables.
Unlike many semi-abandoned military sites, Wolin is easy to reach. A train station, Świnoujście Przytór, sits less than a mile and a half away, and a regular bus links the complex to Świnoujście.
In summer, Wolin Island becomes a popular destination for Polish tourists drawn to its long beaches. The bunker city sits beside the white sand at Przytór, and the region's most celebrated beach, at Świnoujście, looks out on Stawa Młyny, a windmill-shaped lighthouse that guides ships into port.
The Wolin Underground City stands at a rare crossroads of Nazi and Cold War history, and functions as a time capsule of the nuclear arms race frozen somewhere between the 1970s and 1980s.
