The official trailer for the film Black 47, about the Great Famine in Ireland in the 1840s.
The cause of the famine was British indifference to the plight of the Irish people when their potato harvests were devastation by potato blight, an oomycete crop pathogen.
For more about crop pathogens and their impact on harvests, and their potential to wreak famine, see page 9 of our report Global Risks to UK food supplies.