As the world marks 60 years since the liberation of Auschwitz, it is not just about remembering. On Wednesday, the Simon Wiesenthal Centre launched what it is billing as one final effort to capture suspected Nazi war criminals in Germany.
Operation Last Chance has already been launched in eight other countries, mostly in Eastern Europe.
Simon Wiesenthal has dedicated his life to bringing Holocaust war criminals to trial
"So far, (in these countries), we've been able to obtain the names of 329 suspected Holocaust perpetrators," says Efraim Zuroff, chief Nazi hunter at the Simon Wiesenthal Centre. "Of those, 79 have been submitted to local prosecutors or will be in the next few weeks. There are several other investigations ongoing."
The campaign offers 10,000 euro ($13,000) rewards for information leading to prosecution. German newspapers will carry adverts with the warning: "Nazi murderers are still among us."
"Germany is the culmination of the project. It offers the most potential suspects, and in Germany there is the political will to prosecute such people," says Mr Zuroff. "The question is whether the evidence will be sufficient."
Often, the evidence is not sufficient. When Italian prosecutors tried to bring three former SS officers to trial last year, for their alleged role in a massacre in 1944, the case collapsed.
A similar trial currently taking place in Munich looks to be heading the same way.
Adolf Eichmann was convicted of Nazi war crimes in 1961
Konstantin Kuchenbauer, a state prosecutor who specialises in these cases, says there are many problems.
"The witnesses are usually very old, often more than 80. They can't, or no longer want, to remember these horrific acts of cruelty. This makes it very difficult to interview these witnesses.
"You have to be very cautious, you have to build up trust, and you have to make it clear to them how important the investigations are."
The process of dealing with war criminals began at Nuremberg, but there were many other high-profile trials afterwards. In 1947, for instance, the trial of female concentration camp guards from the Ravensbrueck camp, which mostly held women prisoners, made international headlines. But very few people were actually punished in the immediate post-war era.
"Not many people were prosecuted, because at the time many Germans were involved in it and they didn't want to deal with such things," says Johannes Wildner, a guide at Ravensbrueck, now a Holocaust museum.
"They wanted to hide it, to not discuss it. So only a few people were prosecuted... (At Ravensbrueck) many were doctors or had other important jobs, and no-one asked any questions about what they had done during the war."
Over the decades, Germany became much more open in dealing with its Nazi past, pushed by - among others - the student movement of the 1960s. It has its own government agency for hunting war criminals.
But despite this, the Simon Wiesenthal Centre says that out of 100,000 indictments since the war, there have been only 7,000 convictions.
Mr Zuroff believes Operation Last Chance also has an educational role. "In countries like the Baltic states, Poland, Romania, Croatia and Hungary, the issue is often to tell the truth about local complicity in the crimes of the Holocaust," he says.
A 1960s trial provided a chilling picture of the machinery of genocide
"This is also true in Austria, where 90% of the calls to our hotline were actually anti-Semitic."
In Germany, public awareness about Nazi crimes is much better, he says.
But in a speech at an Auschwitz memorial ceremony in Berlin this week, Chancellor Gerhard Schroeder pointed to the continued threat from anti-Semitism and neo-Nazis in Germany.
The event came amid an ongoing scandal in Germany. Last week, officials from the far-right NPD party walked out of a minute's silence for Auschwitz victims in the Saxony state assembly.
"The larger issues of historical accuracy, the fight against Holocaust denial, exist also in Germany," says Mr Zuroff.
"In the meantime, it's only on the periphery, but of course we all know how Hitler started and we all know that he was able to force his way into the mainstream, and gain the support of the majority of Germans.
"So in that sense, we hope that Operation Last Chance will contribute to the fight against Holocaust denial and against anti-Semitism."