ey parts of Arizona's controversial immigration law have been been blocked by Susan Bolton, a US judge, who said:

"There is a substantial likelihood that officers will wrongfully arrest legal residents" - and that Arizona had no right to enforce federal immigration rules.

To its supporters, the law is needed to stop the flow of illegal immigrants from Mexico overrunning Arizona, and fueling rising crime rates.

To its opponents, including the Obama administration, it would lead to wrongful arrests and ethnic profiling.

Already, some migrants have been driven out of the US and into Mexico - a country that many do not really know.

Al Jazeera's Mariana Sanchez reports from the Mexican border city of Nogales.