Nuremberg wants to demystify its Nazi buildings

That is the question now facing Nuremberg, site of the infamous vast marching grounds and torchlit parades immortalised by filmmaker Leni Riefenstahl.

As it prepares to mark the 75th anniversary of the post-war trials of Adolf Hitler's top henchmen, the city has opted to throw itself into a massive conservation effort tied to Germany's vaunted culture of remembrance and atonement for past crimes.

"This is where it all began: the destruction, the exclusion and in the end, the Holocaust" in which the Nazis slaughtered six million European Jews, said Julia Lehner, the southern city's chief culture official.

Touring the sweeping Nazi party rally grounds, Lehner pointed out the massive Zeppelin grandstand where Hitler from 1933 to 1938 delivered racist tirades to half a million party faithful who gathered there every September.

Tens of thousands more Germans from across the country joined in to witness the giant dance spectacles and colour guards.

Nearby, another ruin looms. 

The classical Congress Hall, never completed, is the second largest Nazi-era building still standing, after the Prora recreation complex on the Baltic Sea.

Its "monumentality" was intended, like so many architectural relics from the era, to "intimidate and fascinate" while "demonstrating the superiority of Nazi ideology", said historian Wolfgang Benz.