Dia de Muertos, or Day of the Dead, celebration in Longmont began 24 years ago at the Longmont Museum. The longest running Dia de Muertos celebration in the state of Colorado has become a citywide event that attracts over 6,000 people to the Longmont Museum and Downtown Longmont. The event is a collaboration between the Longmont Museum and local individuals and organizations to make the event authentic and respectful.