In the time it takes to unpack a picnic, something went wrong on the lake. The inflatable turned over, spilling an 11 year- old girl and her nine-year-old friend into the water. The nine- year-old, unable to swim, thrashed out in panic; her friend tried to keep her head above water. Others screamed for help.
Two hundred people stopped eating sandwiches, playing Frisbee or walking the dog, and stood. Some moved to the bank and watched the girl drown. No one tried to help.
'The little girl had already disappeared under the water by the time the police arrived; they called for help and just six people came forward, no one else wanted to get wet, they just watched, passively, from the side,' said Wim de Rooy, of the Rotterdam police, scarcely able to conceal his contempt. Other witnesses said that there had been a lively discussion on the bank about the fact that the girl was Moroccan, perhaps an illegal immigrant. Even when it was clear she had drowned, no one wanted to help the fire brigade trawl the lake: the body was found the next day when the water was pumped out.
The scene, captured on an amateur video, has been played over and over again on the television news. The drowning has become one of those incidents that seize the public imagination and are held up as a reflection of national unease. The Netherlands has been stunned into a rare moment of self-examination.
A country that prides itself on its egalitarian, homogeneous, decent and moral society, with a well-developed sense of community, has been forced to consider its darker side.
With a mixture of shame and incredulity, anthropologists and psychologists have wondered if Dutch society has become too institutionalised. Have social relations been over-emphasised to the detriment of individual initiative? The police toyed with the idea of bringing bystanders to book for 'failing to assist someone in mortal danger and non-cooperation with the police', but decided that it would be impossible to identify them. Some witnesses, notably the man who captured public apathy on video, said people did try to help, but it was not clear from the bank that the girl was drowning.
In Belgium, the drowning and its aftermath have been widely reported.
Belgian psychologists have been explaining the phenomenon of 'dilution of responsibility' in large crowds. Though not explicit, there is a certain schadenfreude in the reporting. The Belgians resent what they perceive as the holier-than-thou attitude of the Dutch.
Belgium may require its citizens to register their every public move with the authorities, and the state may be politically corrupt. But, it is implied, at least people look after each other.
The village of Bilstain has put this assumption to the test. Bilstain has become notorious for turning an HIV-positive three-year-old away from school. When the boy, who comes from Poland and is adopted, first went to school his mother was unaware of the diagnosis. When it became known she informed the school - at which point some teachers refused to have him in class.
Rumours spread and parents began moving their offspring elsewhere, until on 18 August, the school held a public meeting to explain there was no risk. At least a dozen parents remain unconvinced and the nursery school has had to split into two classes.