A priest led fifty men with axes and wet hides to redirect Mount Etna's lava — it worked, until the neighboring town chased them off with weapons.
On the night of March 10–11, 1669, weeks of mounting earthquakes around Mount Etna culminated in a nine-kilometer fissure tearing open on the volcano's southern flank, destroying the town of Nicolosi as it split. Lava began pouring from the new vent almost immediately, at times surging above 600 cubic meters per second.
The flow moved south with terrifying speed, burying the villages of Malpasso and Mompilieri within a day and reaching Mascalucia the day after that. By the time it finally stopped, the eruption had destroyed roughly fourteen towns and villages and buried nearly 40 square kilometers of Sicilian countryside.
As the lava bore down on the city of Catania, a priest named Diego Pappalardo gathered about fifty men from his hometown of Pedara and marched out to fight the flow directly. Wrapped in water-soaked animal hides to survive the heat, they hacked at the lava's hardened outer crust with axes and picks, trying to breach its wall and bleed the molten rock off in a new direction.
It worked. Pappalardo's crew tore open the flow's margin and successfully diverted a portion of the lava away from its path toward Catania — the first time in recorded history anyone is known to have deliberately altered the course of an active lava flow.
The victory didn't last. The redirected lava was now heading straight for the town of Paternò, and roughly 500 armed residents rushed out to stop Pappalardo's men before they could finish the job. Facing a crowd defending their own homes, the diggers retreated, the breach they had cut slowly healed shut, and the lava resumed its original course toward Catania.
Catania's walls held the advancing flow back for about fifteen days after it reached the city's edge in mid-April. Beginning April 30, the lava finally overtopped the ramparts and pushed into the city itself — though contemporary accounts from the time record no confirmed deaths. Later popular claims of 10,000 to 20,000 fatalities are now considered a myth with no basis in the historical record.
The eruption didn't stop until July, 122 days after it began. Molten rock kept flowing into the Ionian Sea for weeks, building a new lava delta that pushed Catania's coastline forward by 800 meters. Castello Ursino, a fortress originally built to guard the shoreline, has stood stranded far inland ever since.
Pappalardo's failed diversion became a legal cautionary tale. By the 19th century, Sicilian custom held that anyone who diverted a lava flow could be held liable for whatever damage it caused elsewhere — a rule only formally set aside once, during a 1983 eruption, when authorities used explosives and concrete barriers to steer lava away from a mountain refuge.