By Adam Parsons
BBC sports correspondent in Berlin
The curious thing about visiting Berlin's Olympic stadium - the Olympiastadion - is that it feels remarkably familiar, even if you're seeing it for the first time.
All that black and white film of the 1936 Olympics, where Jesse Owens punctured Adolf Hitler's pride; all those images of the Olympic flame shimmering against a Nazi flag.
The 1936 Olympic venue hosts another spectacular 70 years on
To visit this stadium feels rather like taking a tour of a historic building rather than a World Cup venue.
Yet this is where Germany's World Cup will begin and end, from a ceremony to start the tournament to the razzmatazz of the final itself - it is the heart of the World Cup, but it is taking a battering.
The most famous stadium in the host country is unsafe. That, at least, is the conclusion of a report drawn up by the nation's leading consumer pressure group, a sort of German equivalent of Which? magazine.
Berlin wasn't the only stadium the group slated - three others came in for criticism - but it was the one that prickled most against the allegations. And so, too, did the World Cup organisers, decrying the report as unwarranted interference.
The report claimed the Olympiastadion had too few handrails, that the stairs were too steep and that a moat that ran around the edge of the pitch would stop fans escaping on to it in the case of a serious emergency. Changes were demanded.
A few days ago, I stood and peered into the moat in the company of the stadium's avuncular manager.
"It's been here for a long time and we've not had a problem with it," he said, clearly weary of having to defend his beloved arena. "These people came along with their own ideas and have caused a lot of disruption. It's upsetting."
The stadium authorities plan temporary bridges over the moat
In some ways, I felt sympathy for him. The stairs didn't seem that steep, and once you get to the top, you walk straight out of the stadium and into a wide apron of empty land.
Hertha Berlin play here week in, week out, and the stadium authorities are used to dealing with big crowds.
But then I went down into the moat, and felt anxious. It is 10ft deep, and too wide to leap across. You can't escape the fact that, in the wake of the Hillsborough disaster, a feature like that wouldn't be allowed in an English stadium.
The stadium authorities shrug when pressed, talk of it adding to safety, and then say that it's a listed feature and can't be tampered with.
They do have a contingency plan, which involves dropping temporary bridges into place over the moat, but it didn't work too well during an evacuation test.
In fact, from the film we have of that test, it seemed utterly inadequate.
The German government has promised action over concerns
The Germans are responding. When we spoke to the sports minister, he promised immediate action and agreed something had to be done.
Yet so far, there's not much sign of remedial work being carried out.
I'm sure the Olympic Stadium will be a fabulous World Cup venue - it is evocative, imposing and vast. But it could be better.
Unless that moat is changed, anybody who saw the horrors of Hillsborough unfold will feel just a little uneasy.