When wells made clean drinking water available in every village in Bangladesh, the feat was greeted as a major public health victory. But in a bizzare turn of events, Bangldesh's tubewells have been secretly poisoining villagers. Arsenic has been traced to the ground water that villagers have been drinking and using for farming for the past 20 years. Thousands of Bangladeshi villages have been unwittinig victims of what may be the biggest mass poisoning in history. As millions continue to be at risk of further contaimination, the World Bank is working with its partners to end the tragedy.