The bicycle may seem like a symbol of leisure or health today, but its roots lie in disaster. In 1815, Mount Tambora in Indonesia erupted with extraordinary force, blasting ash, gas, dust, and rock high into the atmosphere. (It’s now considered the largest volcanic eruption in recorded history.) The fallout dimmed the sun worldwide, lowering temperatures and devastating harvests. The following year became known as the “year without a summer” — snow fell in July in New England, crops w...
