San Salvador Ross wastes no time immersing himself in the dangerous world of the Mara Salvatruchaor MS13 gang. "El Salvador has a level of violence that far exceeds any other country I've been to," says Ross, "there are on average 11 murders a day in a country with a population smaller than London."

Ross's examines Middle America's gang culture with a visit to St. Louis, Missouri; where he takes a look at how an average Midwestern municipality where in a population of 342,000 people, there are around 380,000 guns – and many of these are in the hands of gang members.