Thousands of Central Americans brave the long and often dangerous journey to the US-Mexico border every year. They have escaped violence or poverty - often both.
They have found strength in numbers travelling in what became known as migrant caravans, seeking asylum and a better life north of home. But these caravans have become flashpoints in the fierce debate over immigration in the United States.
For a year and a half, correspondent John Holman walked with Central Americans, witnessing first-hand the cycle of hope and despair.
