In 1816, summer never came. Crops failed in June. It snowed in July. Families across the Northern Hemisphere watched their harvests die in the ground and had no idea why. A volcano on the other side of the world — Mount Tambora in Indonesia — had erupted the year before with a force so massive it put enough material into the atmosphere to change the climate of an entire hemisphere. The people starving in Vermont and Ireland and Bengal had never heard of it.

Host Shawn Spainhour takes you through the full story: the eruption of Tambora in April 1815, the slow creep of its effects across the globe, the famines and food riots and mass migrations it triggered, the new strain of cholera it helped unleash, and the strange red sunsets that painters couldn't stop painting. And on the shores of Lake Geneva, a young woman named Mary Shelley — stuck i ...