One of President Trump's campaign pledges was the construction of a wall along the US-Mexico border. But how would a wall stop drugs and people illegally entering the US? Juan Paullier travels the whole frontier to find out. In Nogales he meets one of the people smugglers who believes the wall will make it more expensive to get into the US. And in Tijuana, Chris is a tattooed ex-gang member trying to start a new life after he was deported from the US.