A border of more than 3,000 kilometres separates the US from Mexico - but it is defined not only by physical barriers made of concrete and steel but by an immigration policy which is failing to address the issues behind illegal migration. Despite the US spending billions of dollars on border enforcement, the lure of work sees illegal migrants enter the country at a rate of 850,000 a year. A series of walls along the Mexican border were designed to stem this flow but based on current estimates it has failed. Instead, the walls have re-routed human traffic into remote desert areas where people risk their lives in deadly conditions attempting to enter the US. This film shows what US immigration policy looks like on the ground for the people making the perilous journey for a better life, and for the Americans who call this borderland home. Update: Since this film first aired on Al Jazeera English in 2007, the US continued to increase spending on border security. At no other time in history has there been as many border patrol officers on duty as there are today. And now the authorities are bracing for a new challenge: children. Since 2014, the number of families and unaccompanied children apprehended at the border keeps skyrocketing. Young people are filling family detention centres near the border, having fled poverty or extreme violence in Central America. And today the issue is taking centre stage in this US presidential election, with Donald Trump calling for more walls, leading some migrants to say they will cross the border now before it may be too late. - Subscribe to our channel: http://aje.io/AJSubscribe - Follow us on Twitter: https://twitter.com/AJEnglish - Find us on Facebook: https://www.facebook.com/aljazeera - Check our website: http://www.aljazeera.com/ #USMexicoBorder #AlJazeeraFeaturedDocumentary