In September of 1984, at least 751 people got violently sick in Dalles, Oregon. At first, no one in the town could figure out why. Those sickened had all eaten at ten different restaurants in the area, but local health officials couldn't find a common food that may have caused their illness. A year later, they finally figured it out: A local cult was trying to swing an election in its favour. The event remains the single largest bioterrorism attack on US soil.