Legal segregation in the US may have ended more than 50 years ago. But in many parts of the country, Americans of different races aren't neighbours - they don't go to the same schools, they don't shop at the same stores, and they don't always have access to the same services.
In 2016 the issue of race will remain high on the agenda in the United States. The police killings of unarmed black men and women over the past few years reignited a debate over race relations in America, and the reverberations will be felt in the upcoming presidential election and beyond.
Ferguson, Baltimore and Chicago are three cities synonymous with racial tensions - but all three have another common denominator. They, like many other American cities, are still very segregated.
In my reporting across the United States I've seen this first hand - from Louisiana to Kansas, Alabama to Wisconsin, Georgia to Nebraska. In so many of these places people of other races simply don't mix, not through choice but circumstance. And if there's no interaction between races, it's harder for conversations on how to solve race problems to even begin.
Newly released census data, analysed by the Brookings Institution, shows black-white segregation is modestly declining in large cities, but it remains high. If zero is a measure for perfect integration and 100 is complete segregation, analysis from Brookings showed most of the country's largest metropolitan areas have segregation levels of between 50 to 70.
According to the Brookings report, "more than half of blacks would need to move to achieve complete integration" .
Some have pointed out that the wording of this part of the report itself highlights the challenges in these issues - why can't this be measured in the number of whites who would have to move?
America in Black and White, a four-part radio documentary, will air next on BBC World Service on 14 January 2016. Listen to the first episode.
Racial and socioeconomic segregation are closely linked - if you're a black person in America, you're more likely than a white person to live in an area of concentrated poverty.
This isn't simply a matter of choice, or chance. Some of it is by design - and do