Just weeks after the Nazi blitzkrieg overran Poland in September 1939 to spark the start of World War II, 500 captured Polish officers were forced into labor near the border town of Woldenberg, Germany, to build their new accommodations—a prisoner of war camp. By the time the 60-acre Woldenberg Oflag II-C POW camp was completed in 1942, it was a miniature town with a population of 7,000 and even its own internal postal service.

Unlike prisoners in many other Nazi camps, the Polish officers held behind Woldenberg’s walls were permitted to exercise both their bodies and their minds. They played soccer games and learned philosophy, law and mathematics in classes taught by officers who were professors and teachers in their civilian lives. They attended plays staged by professional directors and performed in the camp’s symphony orchestra.

And when war prompted the cancellation of the 1944 Summer Games planned for London—as it had the 1940 Games in Tokyo—the prisoners appealed to their captors to allow them to stage their own Olympics. Many of them still remembered the pride that swelled in their hearts when countryman Janusz Kusocinski won the gold medal in the 10,000 meters at the 1932 Los Angeles Games as well as the despair they felt when they heard that their Olympic hero had been captured and executed by the Nazis after fighting in the Polish army.

The German camp commanders, perhaps recalling their country’s own athletic and propaganda triumph at the 1936 Summer Olympics in Berlin, agreed to the request although they prohibited the captives from staging fencing, archery, javelin and pole vault competitions for obvious security reasons.

According to a 1995 article by Sherwin Podolsky in the journal of the International Society of Olympic Historians, the prisoners printed a colorful Olympic program that featured a crowned athlete on the cover and listed the events and names of competitors. Tickets were issued for spectators to sit in grandstand seats. The camp’s post office even printed a commemorative stamp depicting a runner breaking through a finishing-line tape.

On July 23, 1944, the prisoners gathered in a field to stage the opening ceremony. ‘” The excitement in the entire camp was unbelievable,” former prisoner Arkady Verjizinsky told NBC for a feature that aired during the 2004 Summer Games. “All of us were there, some 6,000 men. We were all there together. This was a great moment, and then the Olympic flag went up, the only one in the world, just in this spot.”

The makeshift Olympic flag hoisted by the prisoners certainly looked familiar—but their banner was fashioned from a white bed sheet and colorful scarves that formed the five interlocking Olympic rings. Both captors and captives saluted the banner as it was raised to the sky.

For the next 21 days, the prisoners competed in soccer, basketball, volleyball, track and field, handball and additional sports. According to a 1996 article in the Olympic Review by Iwona Grys, director of the Museum of Sports and Tourism in Warsaw, Poland, 369 prisoners participated in 464 competitions, meaning some captives played more than one sport. As was Olympic tradition at the time, competitions were also staged in cultural events such as painting, sculpture and music.

Winners received diplomas and medals made from embossed paper. However, there were no medals awarded in boxing, which proved too bruising for the prisoners’ weakened bodies. The boxers suffered such an inordinate number of injuries and bone fractures that only half of the 60 scheduled matches were completed before the event had to be abandoned.

According to Grys, the POWs at Woldenberg weren’t the first to stage an Olympic-style competition while being held by the Nazis. Four years earlier, soldiers from Belgium, France, Great Britain, Norway, Poland, Russia and Yugoslavia who were held captive in Stalag XIII-A near Nuremberg, Germany did the same—only their competition was kept a closely guarded secret from their Nazi captors. The competitors at these 1940 games crafted a flag from one of the captive’s shirts and used crayons to draw the Olympic rings and banners representing the home countries of the participating athletes. On behalf of their fellow competitors, prisoners from Poland, France and Great Britain swore an oath “in the name of all the sportsmen whose stadiums are fenced with barbed wire.” With that, they declared open the “International Prisoner-of-War Olympic Games.” (According to Podolsky, another POW Olympics was also held by Polish officers in the Gross Born camp during the summer of 1944.)

The horrors of war quickly returned after the brief respite of the POW Olympics. As Soviet troops closed in on Woldenberg in January 1945, the Nazis forced the prisoners to march hundreds of miles through the most brutal of winter conditions for resettlement in another camp. When the Americans finally liberated them in April 1945, they found only 300 of the Woldenberg prisoners had survived.

The makeshift Olympic flags from the Woldenberg Oflag II-C and Stalag XIII-A camps survived as well. Both are now in the collection of Poland’s Museum of Sports and Tourism along with other artifacts from the prisoner-of-war games, serving as tangible reminders of the Olympic spirit that remained lit during the darkest days of the 20th century.