The crowd surge last year led to the crush in a narrow alley in Itaewon, a disaster that many people in Seoul blamed on a lack of preparation and crowd control measures, with early calls for help going unanswered.
About 3,000 people gathered in front of Seoul city hall after visiting Itaewon to mourn the victims. Families of victims called for the special legislation of a bill to find out the truth behind the tragedy.
Last year's tragedy prompted a police investigation that ended in an acknowledgment of negligence and a poor response by the authorities, referring 23 officials for prosecution, but no senior government officials have resigned or been removed over the disaster.
In the days before Halloween, seasonal decorations normally adorn the alleys that house the district's hottest nightclubs and bars, but this year, posters and flowers commemorating the dead took their place, and young people celebrated elsewhere.