The document provides context about the "Year Without a Summer" of 1816. It describes the massive eruption of Mount Tambora in April 1815, which ejected tens of cubic kilometers of ash into the atmosphere and led to global climate anomalies the following year. The ash cloud from Tambora caused temperatures to drop across Europe and North America in 1816, leading to heavy rains, frosts in summer, and crop failures. This motivated Lord Byron, the Shelleys, and John Polidori to have a ghost story contest at Villa Diodati by Lake Geneva that summer, which directly inspired Mary Shelley to write Frankenstein.