Hundred of couples, holding hands with their young children and many shedding tears, visited the graveyards where eight-year-old Julie Lejeune and Melissa Russo, and An Marchal, 17, and Eefje Lambrecks, 19, were buried.
They also stood before the houses owned by Marc Dutroux, the man alleged to have run the paedophile ring which kidnapped and murdered them.
The child-murder and sex scandal has rocked Belgium since the girls' bodies were discovered over the summer, triggering nation-wide strikes and demonstrations across the country.
Meanwhile, in Croatia, Croat refugees from Eastern Slavonia made their first visit in years to the Serb-held enclave to commemorate their dead and catch a glimpse of their homes. Some 40 buses carrying more than 2,000 refugees crossed to Serb-held territory escorted by the UN civil police, and joint Croat-Serb police patrols. Men and women, some dressed in black and carrying flowers, were allowed a one-hour visit to 30 grave sites scattered all over Eastern Slavonia.