Facebook party invite leads to riot
In the Netherlands, riot police were called in to contain the situation when thousands of youths descended on the northern town of Haren after an online invitation to a girl's 16th birthday party went viral.
The girl and her family had to leave their home as thousands of young people turned up in response to a message she had posted without marking it as a private event.
More than 20 people were arrested and three people were seriously hurt.
Anna Holligan reports.