The purportedly longest escape tunnel dates back to WWII and was discovered on the site of a former German camp for prisoners of war (POW), located in Borne Sulinowo (Ger. Gross Born), northwestern Poland.
The search was conducted by the Polish State Forests, the local museum and passionate volunteers from all over Poland, who aimed to find the exact location and route of the tunnel. According to the initial analysis and georadar measurements, the structure was 7 metres deep and 140 metres long.
While the facility was in use from 1939, Oflag II-D camp was established to house French officers from the Battle of France in mid-1940. The prisoners dug the tunnel between September 1941 and March 1942, when, mid-way through the month, 17 prisoners used it as an escape route.
Should the supposed tunnel length be confirmed by additional geodetic measurements, it will be the longest escape tunnel made by prisoners of war during WWII.
So far, Stalag Luft III, located in the vicinity of Żagań, western Poland, was considered to be the longest tunnel at around 111 metres long.
The story of the tunnel from Stalag Luft III was popularised thanks to the US film directed by John Sturges - "The Great Escape", starring Steve McQueen. The film was nominated for the Golden Globe Award in the Best Drama category in 1963.