Hurricane Katrina is the deadliest flood event in the U.S. in the past 25 years.

Next week, on Aug. 29, will mark twenty years since the disaster.

The storm crashed into the Gulf Coast and devastated coastal Mississippi and New Orleans, where people had to be rescued by boat and helicopter from rooftops.

The dangers were magnified when water breached flood walls and levees, submerging 80% of New Orleans.

The costliest storm in U.S. history caused nearly 1,400 deaths and an estimated $200 billion in damages.