Twenty years later, Hurricane Katrina remains tied as America's costliest storm at $125 billion, though it ranks only fourth in intensity among U.S. landfalls.
Twenty years after Hurricane Katrina devastated New Orleans, the city has invested $15 billion in flood protection while still rebuilding its population and communities.
It's hard to imagine what it must have been like to be inside this place as Hurricane Katrina laid waste to the city, making things as dangerous inside as they were outside.