The Little Ice Age was a period of cooling between the 14th and 19th centuries where temperatures across Europe and North America dropped between 6-14 degrees Fahrenheit. This caused colder winters and the expansion of glaciers, destroying crops and resulting in widespread famine and disease that killed thousands. Potential causes included reduced sunspot activity, large volcanic eruptions blocking sunlight, and interruptions to ocean currents. Significant events during this period included the freezing of the River Thames in London and New York Harbor. The Little Ice Age impacted history through failed exploration attempts, the demise of Viking settlements in Greenland, and agricultural innovations like growing turnips.