Ten people have been charged in a massive stampede that killed 21 people at Germany's Love Parade electronic-music festival in 2010.
Four city workers and six private event organizers face a range of charges from bodily harm in involuntary manslaughter. If convicted, they could face up to five years in jail.
A reported 500,000 people attended the festival in Duisberg. The venue, a former rail yard, was equipped to handle only 250,000.
City prosecutor Horst Bien said that the event's failings, including a single entry point that was too narrow, were evident from the beginning, and that the city should not have issued a permit for the event.
"Something happened on 24 July 2010 that should never have happened," Bien told news organizations including the Guardian. "We weren't looking to see who was morally or politically responsible but instead focused only on who was criminally liable."
Eight foreigners from elsewhere in Europe as well as Australia and China were among those crushed in the melee as fans tried to move through an underpass to gain access to the festival.
"Mistakes in planning were the main reason for the disaster," Bien said.