Chattanooga once had the unflattering distinction of being one of the dirtiest cities in America. Since Walter Cronkite made the pronouncement on the evening news almost four decades ago, Chattanooga has cleaned up its act. It has gone from a smog-filled metropolis with a deteriorating downtown to one of the hippest — and greenest — cities in Tennessee.

One of the most visible indicators of Chattanooga's commitment to being green is the Walnut Street Bridge. The wooden bridge that spans the Tennessee River became too worn to accommodate car traffic and construction on a new bridge was in the works. Instead of tearing it down, the Walnut Street Bridge was left as a pedestrian bridge and has become one of the most popular spots for taking in the views of downtown Chattanooga.

And those views are better than ever thanks to a commitment to reduce air pollution. In 2005, Chattanooga signed an Early Action Compact with the U.S. Environmental Protection Agency that formalized its dedication to combating air pollution. The city's efforts have paid off: Last year, the EPA officially recognized Chattanooga for its success in meeting the latest air-quality guidelines.

The endless list of eco-friendly restaurants, shops, recreational activities and attractions make Chattanooga a great place to spend a weekend — or a lifetime.

Taste green

There's no shortage of restaurants serving dishes made with organic and locally grown foods. One of the most popular is 212 Market (named for its street address), which has the distinction of being the first green-certified restaurant in Tennessee. The menu is designed to reflect the freshest local ingredients and includes items such as bison chili, spinach and walnut ravioli, and homemade ice cream and sorbet. Chef Maggie Moses has taken green to the next level, composting food waste, using renewable power and sending diners home with to-go boxes made of corn.

St. John's Restaurant is another restaurant known for including local fruits and veggies on its menu. The organic local lettuce plate (a sampling of roasted pears, pistachios and goat cheese served over organic greens) is a good example. Vegetarians can find a menu chock-full of local ingredients at Country Life Vegetarian Restaurant and Bakery . It's the only 100 percent vegetarian restaurant in Chattanooga.

Play green

Chattanooga is paradise for outdoor enthusiasts: There are bike and pedestrian paths along the riverfront, a rock-climbing wall at the base of the Walnut Street Bridge and paddlers dot the waters of the Tennessee River.

There are miles of trails on Lookout and Signal mountains. One of the best — and most difficult — is the Cumberland Trail .

The entire trail runs 303 miles from Tennessee to Kentucky, including a 34-mile segment that runs through Chattanooga. The trail follows the line of high ridges and deep gorges that run along the Cumberland Plateau, climbing to 2,000 feet above sea level and plunging into ravines with peek-a-boo views of downtown Chattanooga amid towering hemlocks and ancient rhododendrons.

You can also explore Chattanooga in a kayak. The contrast of herons and hardwood canopies on Maclellan Island with cars and contemporary buildings in downtown Chattanooga make a trip down the Tennessee River an unforgettable experience. Outdoor Chattanooga offers sunset kayak tours that are definitely worth checking into.

Buy green

Chattanooga is an arts town. Look for the work of local artists in galleries in the Bluff View Art District and on the North Shore to find souvenirs that exemplify local culture. The World Next Door is a funky shop in downtown Chattanooga that sells fair-trade items from around the world. Stop in for journals made from elephant dung, messenger bags crafted from used feed and rice bags, or handmade copper bells.

On the weekends, local artists sell their wares at the Chattanooga Market . The outdoor market is a great place to find clothes, jewelry, artwork and locally made foods, including preserves and baked goods.

Travel green

Most of this compact Southern city can be easily explored on foot. The 13-mile paved path along the Tennessee River connects some of the most popular sights and attractions in Chattanooga, including the Tennessee Aquarium and the Hunter Museum of American Art .

Public transportation is also an option. A free electric shuttle runs through downtown, linking the historic Chattanooga Choo Choo with the riverfront and the fleet of public buses includes 12 hybrid vehicles — a ride without the guilt.

Destination of the Week: Chattanooga
With cleaner air and a greener flair, the formerly filthy Scenic City now lives up to its name.