It started as a Saturday trip to Belgium's coast, a chance to escape a heat wave and coronavirus restrictions for a while. As the tide came in, the beach got crowded. Someone complained about the music being too loud. The mood quickly turned ugly.
Within minutes, dozens of people were battling it out on the sands. Some beach-goers threw bottles and umbrellas at police officers who intervened.
By Sunday, a "gang of outsiders" was being blamed, and two coastal communities had banned day trippers from the city.
Officers stood ready at railway stations and blocked traffic, turning away people who can't afford to live, work, or pay for hotel reservations in the area. Local authorities have banished day-trippers, who include many minorities, from Belgian cities or France from its 15-kilometer stretch of sands until the heat wave - which saw temperatures of up to 36 degrees Celsius is over.
At first, the national rail service SNCB resisted calls to cut the number of beach-bound trains, but caved in as political pressure mounted and will now provide fewer this coming weekend.