Baltimore - This city is often cited as the classic example of one that revitalized its waterfront. City leaders decided in the 1960s to make the crime- and rat-infested area around a crumbling downtown harbor the centerpiece of a renaissance based on Baltimore's maritime past. Old wharves, warehouses and a rail yard were torn out. Shops, restaurants and hotels went in, then an aquarium (which led other cities to build aquariums, among them Tampa) and finally a baseball stadium. The cost: an estimated $1 billion. The dividend: Baltimore's Inner Harbor has made the city world-famous and generates an estimated $500 million per year in business. Chattanooga, Tenn. - After leaders decided in the 1980s that the crumbling downtown had to be saved, the city demolished abandoned factories along the Tennessee River and launched a revival by building a $45 million aquarium in 1992 and surrounding it with a $10 million park. Next came a parking and shuttle system, an art museum, a children's museum, an aquarium expansion that's to be finished next year, and a rich variety of residential and commercial development - all designed to harmonize with Chattanooga's architectural style and built around green spaces. Now a riverwalk is going in, along with two more waterfront condominium projects costing $20 million each.

Jacksonville - Bisected by the winding St. Johns River, Jacksonville began dressing up its riverfront 20 years ago. First it built the 27-acre Metropolitan Park on the river's north bank for $4 million. The park includes gardens, picnic areas, a riverbank sidewalk and a water taxi service to other parts of the city. Concerts and a Fourth of July fireworks display are held there. AllTel Stadium, home to the NFL's Jacksonville Jaguars, was built just behind it. In 1985, a year after the park was finished, an $8 million riverwalk was opened on the river's south bank. Although only 1 1/4 miles long, it includes restaurants, bars, shops, museums and a marina. Now the city is building a 3 1/4-mile riverwalk on the north bank. It should be finished by the time Jacksonville hosts the Super Bowl in January.

Providence, R.I. - This city is often cited as a spectacular example of a successful riverfront renaissance. It began with a project to moderate the course downtown of the Woonasquatucket and Moshassuck rivers. Then a downtown park, Waterplace, was built, followed by a mall. The park includes a 1 1/4-mile brick riverwalk and a grand staircase that doubles as a 400-seat amphitheater. Concerts are held there, along with evening torchlight displays. The park covers 4 acres and cost $4.8 million. The mall, Providence Place, was built across the street for $455 million in private money, coupled with more than $200 million in tax incentives over 30 years. It's occupied by trendy shops and restaurants, generates nearly $10 million in sales tax revenue annually, and has helped spark an extensive revival in surrounding neighborhoods.

San Antonio - The Paseo del Rio (usually translated into English as Riverwalk) attracts more than 8 million visitors a year, surpassing the Alamo, and is considered by many to be the No. 1 tourist attraction in Texas. It's also the oldest U.S. waterfront revitalization effort. The foundation for it was a $300,000 federal grant in 1938 that helped to build walkways, arched bridges and entrance steps along 2 1/2 miles of the San Antonio River. But the modern version of it wasn't begun until 1967, when the city started a $2 million expansion. The result is an appealing ribbon of green spaces, sidewalk restaurants, shopping, nightclubs and high-rise hotels, coupled with river cruises. In 2002, Riverwalk contributed an estimated $7.2 billion to San Antonio tourism, including $41 million in revenue from a hotel tax.

Research by ANGIE DROBNIC HOLAN and MICHAEL MESSANO