A New Scientist Histories column from ’05 noted that the last really huge volcanic eruption led to the invention of the bicycle:
ON 5 April 1815, Mount Tambora in Indonesia began to grumble. A week later the volcano blew its top in a spectacular eruption that went on until July. It was the biggest eruption in recorded history, killing around 92,000 people and ejecting so much ash into the atmosphere that average global temperatures dipped by 3 °C. In the northern hemisphere 1816 became known as the year without a summer. New England had blizzards in July and crops failed. Europe was hit just as badly.
On holiday by Lake Geneva the 18-year-old Mary Shelley and her husband Percy were trapped in Lord Byron’s house by constant rain. To divert his guests Byron suggested a competition to write a ghost story. The result was Mary Shelley’s Frankenstein. Across the border in the German state of Baden the soaring price of oats prompted the 32-year-old Karl Drais to invent a replacement for the horse – the first bicycle….