An investigation is underway after at least 18 people were killed in a stampede at the Love Parade festival in western Germany.
Dozens more were injured in the crush, which happened at the entrance to a tunnel in Duisburg near Dusseldorf. Some people had to be resuscitated.
Police say they had closed off the route leading to the parade due to overcrowding. People were told to go back, but panic broke out.
In the late afternoon, many of the hundreds of thousands of revellers were unaware of the tragedy unfolding in the tunnel entrance.
Eyewitnesses said police were warned some time before the crush of a huge build-up of people. The authorities decided not to evacuate the immediate area, fearing further panic.
Emergency services had trouble reaching the victims. A motorway was closed to allow helicopters in to take the injured to hospital.
Organisers had expected more than one million partygoers. There have been suggestions that the venue could not cope with the numbers.
The Love Parade began in Berlin over 20 years ago as a peace demonstration and grew into a massive annual celebration of club culture. Financial constraints and tension with the authorities forced it to move to other German cities three years ago.