From the North Shore to the South Side Chattanooga's getting bigger. According to the 2008 estimated census numbers, the city's population now stands at 170,880 people.

Chattanooga Mayor Ron Littlefield thinks he knows why: "Chattanooga's a great city and people are learning about that and moving here in large numbers, plus a lot of people are staying. Young people who may have grown up and moved away," he said Tuesday.

The city is now a far cry from the early 1990s when the aquarium was only one building, and the downtown Riverfront wasn't '21st Century.' This development became a catalyst for new growth.

Mayor Littlefield remembers a meeting with prominent city planner Jim Rouse 25 years ago: "Someone asked him, Mr. Rouse, how do we make this city grow? And he said it's easy. You make the city the best it can be for the people who already live here and the rest will take care of itself."

More people now live downtown. New condos pop up on the North Shore. Townhouses now line streets like Cowart and Madison on the South Side.  Shannon Smith lives in a townhouse on the South Side.  "It's amazing even after 8 years we still have people drive through and say, "Gosh, we didn't know this was here' and how nice it is," she said while walking her dogs.

The city's population is growing at a time when older, more traditional suburbs are losing people. For example, Lookout Mountain now has a smaller population than Lakesite.  "Everybody wanted to go to the suburbs," says Smith of a few decades ago.  "Now, just everything's downtown and you want easy access and it's just incredible. It's very exciting," she adds.

With the added numbers in the city, property tax revenues go up but so do problems like getting services to people in new locations.

Mayor Littlefield says he thinks Chattanooga will pass Knoxville as Tennessee's third largest city within the next five years.