The Monument to the Murdered Jews of Europe is a remarkable presence at the very centre of the new Berlin. It was designed by the American architect Peter Eisenman, with some initial input from the artist Richard Serra, and was opened nine years ago. It is a huge monument, abstract in form, which must be experienced by the visitor. It is made up of nearly 3,000 concrete slabs, or stelae, in a grid pattern on a site just under five acres. From one side, the surfaces of the slabs form an uneven but roughly flat surface. As you enter the grid pattern, it becomes apparent that the ground undulates and falls away, meaning that the individual slabs are very different; at the edge, they are only a few inches high, in the middle they can be 15ft high.

The experience is very powerful. As you progress, the stelae start to block out the sky; it is almost like being buried in stone towards the middle; and it starts to become hard to see your way out. It is an abstract, powerful metaphor, and it was brave of the Germans to place the memorial so much at the centre of their new/old capital.

My Berlin existence was mostly over 10 or 15 years ago, but I still have friends there, and go regularly. Those Berlin friends are of my generation, and I would say that the one thing they all have in common is that they understand what their nation did, and recognise the importance of prompt and thorough self-examination. The transformation of first West Germany, then Germany as a whole, into a condition of democratic openness is one of the triumphs of 20th-century history.

That’s all over now, apparently. Last weekend, I was in Berlin for two old friends’ wedding, and, passing by the monument, thought I would walk through it again. There are signs asking for quiet, asking visitors to walk slowly and not to leap from stele to stele. Last weekend, it was shocking to see dozens of teenagers and even slightly older people rampaging through the memorial; shrieking with laughter, running, playing tag, screaming and singing songs. Germans. What were they doing there? How did they deal with this lowering and grim space? Not in the way their fathers would have done, with contemplation and consideration. It was not part of their thoughts about this place that anyone else visiting could possibly have been affected by those events, 70 years ago. What were those events? Perhaps they hardly knew.

I confronted one group who had been screaming and chasing each other and smoking a little dope in the deepest part of the labyrinth. What did they think they were doing? A little respect, please, a little quiet; and I am sorry to say that I told them that it was their great-grandparents who tolerated the murder of so many millions. What was their response? Silence: amazed, agape, incredulous. But they seemed baffled rather than ashamed. This was a brilliant place, with all the hiding places and the thousands of different ways through it. Why shouldn’t they run through it, making as much noise as possible? What was it for, again?

Well, there are memorials to the First World War and the Napoleonic wars that we lean against, eating ice creams when it’s sunny. Oblivion settles over atrocity; we say “never again” and have forgotten all about it in 20 years’ time. It’s the natural course of events, but just for this once, could we not hasten things? There are people alive whose families were wiped out. We may have reached the point where even quite serious novelists can joke scandalously about the Holocaust, like Shalom Auslander’s alarming Hope: A Tragedy. But let that not be the default mode, just yet. And someone might explain to the German teenagers running through this maze of stone why they should slow down, and think; and like the generation before them, wonder what their families were doing during that black time.

Turn art into a machine and it can break down

The conceptual artist Michael Landy had, interestingly, never been inside the National Gallery until it invited him to be its new artist in residence. That raises an interesting question, as curators say, but unusually, this interesting question has an answer. His exhibition in response, which opened on Thursday, shows why he wasn’t curious. Unlike all the other artists in the building, he regards art as a sort of exciting fairground ride, full of thrills and spills. What Crivelli’s paintings of martyrs lack is a machine that strikes an animatronic stone against a chest, or a pair of pliers rising amusingly to the teeth of a saint who was tortured in dental ways.

Landy is not alone in wanting to turn art into a series of fun “attractions”. There was that bloke who installed slides at Tate Modern a few years ago, and Anish Kapoor is currently busy firing wax against walls with a cannon at the Martin-Gropius-Bau. But, not for the first time, I reflected that art can be a means of doing something else, only not as well as the professionals. Three-quarters of all video art is just film, done badly. One artist even tried to write a novel, lamentable by comparison with the very worst of Dan Brown. “Sound art” would mostly get you laughed out of any composition class in the country. And Landy’s animatronic sculptures, though all very well and good, have this one problem. They break down. I went on Friday, and already one sculpture, perhaps two, weren’t working. We put up with a lot from our conceptual artists, but we ought to be able to ask that if they say things are going to work, they’ll work. Or was it breaking down in an interesting manner, one which raised all sorts of interesting questions?