When a team of archeologists uncovered a mass grave in East London in the 1990s, they initially hypothesized that it must have been a burial site of victims of the plague. However, radiocarbon testing revealed that the skeletons dated from sometime around 1250 CE, a century before the plague was introduced to Europe. So what happened? Through examining a number of historic manuscripts, archeologist Don Walker discovered that England had experienced a famine, caused by unseasonably frigid weather. In the year 1258 this famine, which killed no fewer than 30% of London's population, was likely caused by a volcanic eruption. This recent episode of PBS's NOVA, which aired on October 25, 2017, explores the science behind how volcanic eruptions impact global climate. This episode includes a consideration of the Mount Laki eruptions of 1783 and 1784, the Mount Tambora eruption of 1815, and the Mount Pinatubo eruption of 1991. Interested viewers can watch the full episode and check out a few related resources.