Claus von Stauffenberg had been severely wounded in North Africa

BBC News Online spoke to one of those experts, Professor Peter Hoffmann of McGill University, about the man who led the conspiracy - and what it means today.

On 20 July 1944 Claus Schenk Graf von Stauffenberg planted a briefcase containing two pounds of explosives in a room at Hitler's headquarters in what is now Poland.

The briefcase was moved behind a table leg before it exploded, protecting Hitler from the brunt of the blast which killed four others in the room.

Stauffenberg was executed within hours. He has been viewed by some in the years since as a traitor, while others regarded him as a hero.

Professor Hoffmann puts him squarely among the latter.

He says Stauffenberg was motivated by a sense of moral responsibility, brought on by his knowledge of the crimes the regime was committing, as well as his belief that some of Hitler's tactical orders had no chance of success.

Stauffenberg felt this amounted to an act of treason against German soldiers, Professor Hoffmann said.

Hitler's bunker is now a tourist attraction in Poland

He says all the plotters knew there was only a limited chance of killing Hitler and that if they failed they would be executed.

Even if Hitler died, their subsequent takeover of the government may not succeed. And even if it did, they had no chance of a political future as the Allies would immediately occupy Germany.

Professor Hoffmann says the conspirators also knew that even if the entire plan worked, they would be regarded as traitors by their countrymen.

"They did it as a sacrifice."

Amateurs?

The plotters have also faced criticism over the perceived amateurish nature of the plan.

Professor Hoffmann dismisses that as well. "One doesn't have command over troops - that is approved at the highest level. How would you get that when you're working against the highest level?" he said.

"The planning was impeccable, but the flaw was the failure to kill Hitler."

That raises a question: Why did a man with only one eye and three fingers have the job of carrying a briefcase packed with explosives into the Nazi inner sanctum?

Professor Hoffmann believes there was no other, easier way. "If there had been, I'm sure Stauffenberg would have liked to have known about it," he said.

Stauffenberg obviously could not handle a pistol, but nor could he stay in the room to ensure the bomb was placed close enough to Hitler to ensure he was killed.

The Stauffenberg plot is one of several Hitler survived

Since the plotters did not know where in the room Hitler would be, they had to plan on killing everyone present. Stauffenberg had to live so he could race back to Berlin - some 500 kilometres away - to signal that it was safe to proceed with the planned coup.

Professor Hoffmann says the plot failed because Stauffenberg was interrupted while he was arming the bomb. As a result, he only packed half the explosives into the briefcase. It was moved, and Hitler lived.

Stories such as the Stauffenberg plot inevitably give rise to speculation. What if he had succeeded? With Hitler dead, how much sooner might the war have ended?

Professor Hoffmann says Stauffenberg would still have needed to escape the bunker and return safely to Berlin. If he could not do that, his co-plotters may not have believed Hitler had been killed and there may not have been a coup.

But, assuming his safe return, Professor Hoffmann thinks the war could have been over in a matter of weeks, saving "four or five million lives".

If most people did not resist, then most people were doing wrong

"It would have saved a lot of cities from destruction, it would have saved hundreds of thousand of Jews who were still being gassed, it would have saved Allied lives, it would have prevented the devastation of parts of France, Poland, Holland and Belgium," he said.

Given that, he says Stauffenberg deserves more attention than he has received in Germany since the end of the war.

"In opinion polls, a majority of respondents say they approve of the resistance and what they have done," he said. Yet the criticisms persist.

He puts this down to the problems confronting the German psyche after the war.

"If it was right to resist, as those who honour the resistance say it is, then it was obviously wrong not to resist. If most people did not resist, then most people were doing wrong.

"Who wants to live with the knowledge that he was doing wrong, that he was allowing himself to be a tool of a criminal?"

THE 20 JULY PLOT Stauffenberg placed a briefcase bomb under the oak table and left One of the table's two heavy supports shielded Hitler from the blast Large windows and wooden walls allowed pressure to escape All present would have died if they had met in a bunker as usual 1. Adolf Hitler 2. Field Marshall Wilhelm Keitel 3. Gen Alfred von Jodl 4. Gen Walter Warlimont 5. Franz von Sonnleithner 6. Maj Herbert Buchs 7. Stenographer Heinz Buchholz 8. Lt Gen Hermann Fegelein 9.Col Nikolaus von Below 10. Rear Adm Hans-Erich Voss 11. Otto Gunsche, Hitler's adjutant 12. Gen Walter Scherff (injured) 13. Gen Ernst John von Freyend 14. Capt Heinz Assman (injured) 15. Stenographer Heinrich Berger (killed) 16. Rear Adm Karl-Jesco von Puttkamer (injured) 17. Gen Walther Buhle 18. Lt Col Heinrich Borgmann (injured) 19. Gen Rudolf Schmundt (killed) 20. Lt Col Heinz Waizenegger 21. Gen Karl Bodenschatz (injured) 22. Col Heinz Brandt (killed) 23. Gen Gunther Korten (killed) 24. Col Claus von Stauffenberg 25. Gen Adolf Heusinger (injured)