(Above, watch the "60 Minutes" profile of Nicholas Winton, which was broadcast in 2014.)
LONDON -- He was just a 29-year-old clerk at the London Stock Exchange when he faced the challenge of his lifetime. Traveling with a friend to Czechoslovakia in 1938, as the drums of impending war echoed around Europe, Nicholas Winton was hit by a key realization.
The country was in danger and no one was saving its Jewish children.
Winton would almost single-handedly save more than 650 Jewish children from the Holocaust, earning himself the label "Britain's Schindler." He died Wednesday at age 106 in a hospital near Maidenhead, his hometown west of London, his family said.
Winton arranged trains to carry children from Nazi-occupied Prague to Britain, battling bureaucracy at both ends and saving them from almost certain death. To top it all off, he then kept quiet about his exploits for a half-century.
His daughter, Barbara, said she hoped her father would be remembered for his wicked sense of humor and charity work as well as his wartime heroism. And she hoped his legacy would be inspiring people to believe that even difficult things were possible.
"He believed that if there was something that needed to be done you should do it," she said. "Let's not spend too long agonizing about stuff. Let's get it done."
British Prime Minister David Cameron said "the world has lost a great man." Jonathan Sacks, Britain's former chief rabbi, said Winton "was a giant of moral courage and determination, and he will be mourned by Jewish people around the world."
Born in London on May 19, 1909 to parents of German Jewish descent, Winton himself was raised as a Christian.
Late in 1938, a friend contacted him and told him to cancel the skiing holiday they had planned and travel instead to Czechoslovakia.
Alarmed by the influx of refugees from the Sudetenland region recently annexed by Germany, Winton and his friend feared - correctly - that Czechoslovakia soon would be invaded by the Nazis and that its Jewish residents would be sent to concentration camps.
While some in Britain were working to get Jewish intellectuals and communists out of Czechoslovakia, no one was trying to save the children - so Winton took that task upon himself.
Returning to Britain, Winton persuaded British officials to accept children, as long as foster homes were found and a 50-pound guarantee was paid for each one to ensure they had enough money to return home later. At the time, their stays were only expected to be temporary.
Setting himself up as the one-man children's section of the British Committee for Refugees from Czechoslovakia, Winton set about finding homes and guarantors, drawing up lists of about 6,000 children, publishing pictures to encourage British families to agree to take them.
The first 20 children arrived by plane, but once the German army reached Prague in March 1939, they could only be brought out by train.
So, in the months before the outbreak of World War II, eight trains carried children from Czechoslovakia through Germany to Britain. In all, Winton got 669 children out.
The largest evacuation was scheduled for Sept. 3, 1939 - the day that Britain declared war on Germany. That train never left, and almost none of the 250 children trying to flee on it survived the war.
The children from Prague were among some 10,000 mostly Jewish children who made it to Britain on what were known as the Kindertransports (children's transports). Few of them would see their parents again.
Although many more Jewish children were saved from Berlin and Vienna, those operations were better organized and better financed. Winton's operation was unique because he worked almost alone.
"Maybe a lot more could have been done. But much more time would have been needed, much more help would have been needed from other countries, much more money would have been needed, much more organization," Winton later said.
He also acknowledged that not all the children who made it to Britain were well-treated in their foster homes - sometimes they were used as cheap domestic servants.
"I wouldn't claim that it was 100 percent successful. But I would claim that everybody who came over was alive at the end of the war," he was quoted as saying in the book about the Kindertransports "Into the Arms of Strangers."
Several of the children he saved grew up to have prominent careers, including filmmaker Karel Reisz, British politician Alf Dubs and Canadian journalist Joe Schlesinger.
Winton served in the Royal Air Force during the war and continued to support refugee organizations. After the war, he became involved in numerous other charitable organizations, especially in Maidenhead.
A keen fencer who lost his chance to compete at the Olympics because of the outbreak of World War II, Winton worked with his younger brother Bobby to found the Winton Cup, still a major team fencing competition in Britain.
But for almost 50 years, Winton said nothing about what he had done before the war. It only emerged in 1988 when his wife Grete found documents in the attic of their home.
"There are all kinds of things you don't talk about, even with your family," Winton said in 1999. "Everything that happened before the war actually didn't feel important in the light of the war itself."
Winton's wife persuaded him to have his story documented. It became well-known in Britain after the BBC tracked down dozens of "Nicky's Children" and arranged an emotional reunion on prime-time television.
A film about his heroism, "Nicholas Winton - The Power of Good," won an International Emmy Award in 2002. Then-Prime Minister Tony Blair praised him as "Britain's Schindler," after German businessman Oskar Schindler, who also saved Jewish lives during the war.
Winton was knighted by Queen Elizabeth II in 2003 and also honored in the Czech Republic, where last year he received the country's highest state honor, the Order of the White Lion.
"He was a person I admired for his personal bravery," said Czech President Milos Zeman.
A statue of Winton stands at Prague's central station, while a statue commemorating the children of the Kindertransport is a popular sight at London's Liverpool Street Station.
Winton continued to attend Kindertransport events in Britain and the Czech Republic well beyond his 100th birthday.
Still, he rejected the description of himself as a hero, insisting that unlike Schindler, his life had never been in danger.
"At the time, everybody said, 'Isn't it wonderful what you've done for the Jews? You saved all these Jewish people,'" Winton said. "When it was first said to me, it came almost as a revelation. Because I didn't do it particularly for that reason. I was there to save children."
Winton's wife Grete died in 1999. He is survived by his daughter Barbara, his son Nick and several grandchildren.