BERLIN - Better check your Facebook settings before posting a party invitation online.

A teenage girl in Germany who forgot to mark her birthday invitation as private on Facebook fled her own party when more than 1,500 guests showed up and around 100 police officers, some on horses, were needed to keep the crowd under control.

Eleven people were temporarily detained, one police officer was injured, dozens of girls wearing flip-flops cut their feet on broken glass and firefighters had to extinguish two small fires at the 16th birthday party in Hamburg, police spokesman Mirko Streiber said Sunday.

The birthday girl, identified only as Thessa, went into hiding - reportedly having cake with her grandmom - but "nonetheless the party was a hit," Streiber said.