You can see the difference best from satellite imagery. This is the corner of 15th and McFarland Blvd., before the tornado hit. Here's an image of the corner just after the storm came through. There's debris everywhere.

This is what that same neighborhood looks like today. We're left here with an empty field where these homes once stood. The tornado was on the ground for less than six minutes, and overall 53 people were killed here in Tuscaloosa alone.

This is going to be the safe room. This is poured-in-place concrete walls.

Residents are rebuilding to be better prepared.

You worried this is going to happen again?

Yes. I mean, I think it's obvious that Tuscaloosa is on the path now.

And though there are signs of progress,

As far as being this -- being in this business, I'm not better off till I get the doors open again.

George Howell, CNN, Tuscaloosa, Alabama.

From Alabama, we're heading north to New York City for what's expected to be a towering achievement.

This time-lapse video shows construction at the area known as Ground Zero. It's the site of the former World Trade Center, the twin towers that were destroyed by the 9/11 terrorist attacks in 2001.

The building that's gone up has the same number as one of those towers, One World Trade Center. The project has been moving along at the rate of about one floor every week. Today, it's expected to become the tallest building in New York City. But it won't stop there. One World Trade Center is scheduled to reach its ultimate altitude, 1,776 feet, some time next year.