WARSAW -- Thanks to American film director Steven Spielberg, many people may think of German businessman Oskar Schindler as the man who did the most to save Polish Jews during World War II.
But in Poland, efforts are under way to bring Schindler-style recognition to a lesser-known figure -- Jan Karski, an eyewitness to the Holocaust whose daring wartime attempts to call attention to the slaughter of Polish Jews were largely ignored by the United States and Britain.
In a year when World War II anniversaries are focused on Normandy in the West and the end of the Leningrad Siege in Russia, Poland is honoring the centenary of the birth of its own wartime hero with commemorative coins, political lectures, and the reissue, in Polish and English, of Karski's 1944 memoir, "Story of a Secret State."
"It's an enormously complex task for Karski to get more recognition, because he remained silent for decades," says Wojciech Bialozyt, a young history buff who directs the Jan Karski Educational Foundation from an elegant office in Warsaw's diplomatic quarter. "He started being recognized in the beginning of the 1980s, and from then it was quite a short period while he was still alive. And in Poland, he was 100 percent unknown."
'This Sin Will Haunt Humanity'
Karski, who died in 2000, spent most of his life in the United States, where he established a distinguished postwar career as a professor at Georgetown University in Washington, D.C. But he is better known for his years as a member of Poland's WWII-era Underground State, the network of secret resistance organizations fighting the dual occupation of Nazi Germany and the Soviet Union, which individually invaded Poland from west and east within weeks of each other in September 1939.
Karski, who was born Jan Kozielewski in 1914
, grew up in a large, working-class Catholic family in the city of Lodz. He went on to join Poland's diplomatic corps and served as a cavalry officer in the early days of the war. Following an escape from a Soviet detention camp, Karski changed his name and joined the underground, where he quickly became a high-value courier, carrying memorized strategic information from Poland to Allied leaders and the Polish government-in-exile in France and London.
A member of the Nazi SS inspects a group of Jewish workers in the Warsaw ghetto in April 1943.
In 1942, as hundreds of thousands of Polish Jews were being deported to Nazi extermination camps, Jewish members of the underground asked Karski to carry the news to the West, where the Nazis' anti-Jewish atrocities had received little attention.
To understand the scope of the killings, Karski adopted a disguise and visited the Warsaw Ghetto, where the Germans were holding captive as many as 400,000 Jews, nearly two-thirds of whom would end up in concentration camps. He also traveled to the Izbica transit camp, where he watched in horror as 46 train cars lined with corrosive quicklime were packed with starving, terrified Jews.
He later described the experience, in harrowing detail, in "Story of a Secret State:"
"My informants had minutely described the entire journey. The train would travel about 80 miles and finally come to a halt in an empty barren field. Then nothing at all would happen. The train would stand stock-still, patiently waiting while death penetrated into every corner of its interior. This would take from two to four days."
Karski traveled west with a plea to make the prevention of the Jewish slaughter an explicit goal of the Allied Powers. He urged both British Foreign Secretary Anthony Eden and U.S. President Franklin D. Roosevelt to consider military strikes against rail lines used for the Nazi deportations and even, at the worst, against Germany's own cultural institutions.
It was a strategy the Allies would ultimately adopt later in the war. But neither official was prepared to take such measures in time to prevent the deaths of 3 million Polish Jews. Karski, one of a handful of people to warn Western leaders of the Holocaust, and its earliest eyewitness, was largely ignored.
Thirty-five years later, the memory still sparked passionate anger in Karski, who used his speech at a 1980 conference of concentration camp liberators to begin a self-described second mission to remind the world of its deadly indifference to the Holocaust.
WATCH: Karski 1980 speech
"The second original sin had been committed by humanity," Karski said, nearly shouting. "Through commission, or omission, or self-imposed ignorance, or insensitivity, or self-interest, or hypocrisy, or heartless rationalization. This sin will haunt humanity till the end of time. It does haunt me. And I want it to be so."
Karski went on to be awarded honorary Israeli citizenship and Poland's highest civilian honor, the Order of the White Eagle, which was presented to him personally 1995 by then-President Lech Walesa.
In 2012, he was posthumously awarded the U.S. Medal of Freedom by Barack Obama, who said of the Holocaust, "We must tell our children about how this evil was allowed to happen -- because so many people succumbed to their darkest instincts; because so many others stood silent."
WATCH: Karski is posthumously awarded the U.S. Medal of Freedom
Karski's supporters are now working to promote his principles of compassionate engagement as a model for foreign policy worldwide.
Poland, which has led efforts to defend neighboring Ukraine throughout its crisis with Russia, has emerged from its World War II occupation and forced transition to communism to become one of the European Union's most vocal advocates of its post-Soviet neighbors and a stubborn counterbalance to rising Russian influence.
Bialozyt says Karski's legacy serves to remind the international community of the responsibility to protect its most vulnerable members.
"His message was neglected. So this is about indifference," he says. "The world was simply indifferent. You can recall a number of examples after the Second World War when the world remained indifferent -- Bosnia, Rwanda, Syria. So this is the great lesson of the Karski mission for the world of today."