Thousands of people are protesting in the US state of Missouri because they say the police there don't treat black people and white people equally.
The unrest started over a week ago when a black teenager called Michael Brown was shot by a white policeman.
People say Michael was walking in the middle of the road, stopping traffic - but he wasn't carrying a weapon.
His death has brought to the surface a lack of trust between the people who live in Missouri and the police.
It's not the first time the police in the United States have been accused of racism, and protestors in Missouri say they want answers.
The police in Missouri have declared a state of emergency.
The authorities have asked the National Guard - a team of men and women from the army - to try and restore peace to the area.
Now President Obama has ordered a full investigation into the death of Michael Brown.