[chris]

On November 20, 1980, an oil drilling rig breached a salt mine beneath Lake Peigneur in Louisiana, allowing the lake to flood the mine.

The mine reportedly took two days to fill. The draining lake formed a roughly 150-foot waterfall, and barges later resurfaced after pressure equalized. No one was reported hurt.

The breach changed the nature of Lake Peigneur entirely. The cause of the drilling accident remained unknown because the evidence was left at the bottom of the flooded mine.