1985 The Val di Stava dam collapses killing 268 people in Val di Stava, Italy.
The Val di Stava dam was actually two tailings dams. Tailings dams are dams made up of tailings from mines. When the overflow pipe became blocked, the tailings liquefied and failed within 30 seconds. When water from any earthen dam overflows the top, the dam will fail immediately releasing hundreds of thousands of cubic meters of water, mud, sand and debris. They will destroy everything in their path.