Wikipedia details my favorite part of the history of that year:
In June 1816, "incessant rainfall" during that "wet, ungenial summer" forced Mary Shelley,[42][43] Percy Bysshe Shelley, Lord Byron and John William Polidori, and their friends to stay indoors at Villa Diodati overlooking Lake Geneva for much of their Swiss holiday.[40][44][43] Inspired by a collection of German ghost stories they had read, Lord Byron proposed a contest to see who could write the scariest story, leading Shelley to write Frankenstein; or, The Modern Prometheus[43] and Lord Byron to write "A Fragment", which Polidori later used as inspiration for The Vampyre[43] – a precursor to Dracula. These days inside Villa Diodati, remembered by Mary Shelley as happier times,[43] were filled with tension, opium, and intellectual conversations.[45] After listening intently to one of these conversations she woke with the image of Frankenstein kneeling over his monstrous creation, and thus she had the beginnings of her now-famous story.[43] Lord Byron was inspired to write the poem "Darkness" by a single day when "the fowls all went to roost at noon and candles had to be lit as at midnight".[40] The imagery in the poem is starkly similar to the conditions of the Year Without a Summer:[46]
