Sometimes people get very angry with each other because of their differences. In Sarajevo, there were some people who were from a group called the Serbs and others who were from a group called the Bosniaks. These two groups had a long history of not getting along, and things got even worse when a Bosniak man was killed by a Serb man.
Many Bosniaks were very upset about the killing and they started protesting in the streets, but things quickly turned violent. They started throwing things like rocks and bottles at cars and buildings, and some even set fire to things. The police tried to calm things down, but they were outnumbered and couldn't stop the violence.
The people who were targeted were mostly Serbs, who were seen as responsible for the death of the Bosniak man. This violence against the Serbs is what is known as the anti-Serb riots.
Even though it's okay to feel sad or angry when bad things happen, it's never okay to hurt other people. The riots caused a lot of damage and hurt many innocent people, and it's important for everyone to remember that violence is never the answer.