Inflicting over $80 billion in damage, and causing the deaths of over 1,800 people, Hurricane Katrina was among the greatest engineering disasters in US history. But was Katrina the "big one" New Orleans had been waiting for? Many believe the "perfect storm" is yet to come. If and when the big one does hit, will New Orleans be ready? The answers are in the underground. From the Army Corps' latest levees to last-ditch efforts to use save New Orleans' vanishing wetlands, we're going deep into New Orleans' underground to see where New Orleans stands, and if it stands a chance.