A 16 year old who advertised her birthday party on Facebook had to call the police as 300 teenagers descended upon her home.
The teen invited one hundred of her friends to the party in her house in Brighton using the social networking website.
But the word got out.
Even though there were adults at the party, Sussex police had to be called to disperse the would-be revellers.
Inspector Andy Richardson told BBC News: "There was a sea of people, the place was overrun".
"We eventually got the unwanted guests out at around 11pm", he added.
But not before the family home was trashed with damaged carpets and a wrecked shed and garden.
The police are now advising against organising parties using Facebook.