For decades in the US, the incarceration rate for African Americans has been much higher than for whites, a racial disparity the US Attorney General Eric Holder has described as "shameful".

In part to address this, Mr Holder unveiled a policy shift that will mean the US locks up fewer people convicted of non-violent, drugs offences.

The state that locks up the highest percentage of black men is Wisconsin. The national average is 6.7%, but in Wisconsin it's 12.8% - more than three percentage points higher than the second-placed state, Oklahoma.

A visit to Milwaukee by the BBC's Franz Strasser provides some of the answers why.

Altered States is a series of video features published every Wednesday on the BBC News website which examines how shifting demographics and economic conditions affects America on a local level.