Joachim Ronneberg - a Norwegian resistance fighter who sabotaged Nazi Germany's nuclear weapons ambitions during World War Two - has died aged 99.
In 1943, Ronneberg led a top-secret raid on a heavily-guarded plant in Norway's southern region of Telemark, earning him the title of the "last hero of Telemark".
Speaking to the BBC in 2013, Ronneberg claimed that he only realised the significance of the mission after atomic bombs were dropped on Japan's Hiroshima and Nagasaki in 1945.
Ronneberg's operation was immortalised in the 1965 Hollywood motion picture, Heroes of Telemark, which starred Kirk Douglas.
Born in the town of Aalesund in 1919, Ronneberg was forced to flee Norway after the Nazis invaded in 1940. However, the then-21-year-old, who escaped with eight friends to Scotland by boat, was determined to return and fight.
At the time, Nazi Germany was in need of what was referred to as "heavy water" - that is water with an extra atomic particle in its hydrogen nucleus - in its race against the Allies to produce an atomic bomb.
Large amounts of "heavy water" - or deuterium oxide - was only made at the Norsk Hydro facility in Rjukan, Telemark, which made it a major target for the Nazis.
When a small team tasked with destroying it in 1942 failed, Ronneberg assembled a team of five other commandoes in an Allied operation they codenamed Gunnerside.
Speaking to the BBC on the 70th anniversary of the mission, the veteran asserted "We were a gang of friends doing a job together."
The task force parachuted onto a plateau, skied across country, descended into a ravine and crossed an icy river before using the railway line to gain access into the plant and set up their explosives.
"We very often thought that this was a one way trip," Ronneberg commented.
After the explosion, the men fled to Sweden - while being chased by around 3,000 German soldiers - by skiing 200 miles across Telemark. With a knowing smile, Ronneberg later described it as the "best skiing weekend I ever had".
This operation (coupled with the successful US air raids the following year), forced the Germans into submission, and has since been described as the most successful act of sabotage of World War Two.
"He is one of our great heroes," Norway's Prime Minister Erna Solberg told NTB news agency in response to the news of Ronneberg's death. "Ronneberg is probably the last of the best known resistance fighters to pass away."
Ronneberg, who had historically been reluctant to speak about the operation - despite numerous books, documentaries and television series retelling the story - broke his silence in the 1970's, with the intention to raise awareness of the dangers of war among youngsters.
"Those growing up today need to understand that we must always be ready to fight for peace and freedom," he said.