When the Exxon Valdez oil tanker spills millions of gallons of crude oil at sea, it contaminates Alaska's pristine coastline and creates an apocalyptic environmental catastrophe. Experts investigate what caused this horrific disaster.
 

The devastating Northridge earthquake struck Los Angeles in 1994, killing 57 people and causing $20 billion in damage in less than 20 seconds; expert scientists and engineers investigate why these structures were not prepared for the violent disaster.