Chattanooga: From 'dirtiest city' to Internet haven (pictures)

The Tennessee River runs through the heart of Chattanooga and was a key element in the city's $120 million plan to revitalize the waterfront.  Included in the plan was the expansion of the Hunter Museum of American Art, which sits on a bluff overlooking the river.

Built in 1890, the 2,376-foot (724 m) Walnut Street Bridge was the first to connect Chattanooga's downtown with the North Shore across the Tennessee River. The bridge was closed to motor vehicles in 1978 and sat in disrepair until the late 1980s. As part of the massive riverfront revitalization effort, the bridge was restored and opened as a pedestrian walkway.

The Chattanooga Riverwalk will ultimately stretch 22 miles from downtown Chattanooga near the Tennessee Aquarium to the TVA Dam and beyond. Currently, about 8 miles of the riverwalk are open and follow the south bank of the Tennessee River, which tourists and residents use to access the river for recreation.

Chattanooga has become a mecca for outdoor enthusiasts. Outdoor Magazine has twice in the past four years named it the "best town ever."

Chattanooga is known nationwide for the miles of hard sandstone bluffs that rock climbers love. High Point Climbing and Fitness in downtown Chattanooga offers 30,000 square feet of climbing inside and outside. The company claims to offer climbing walls for all abilities from beginners to experts.

Entrepreneurs come to Chattanooga for the startup scene and the ultra high-speed broadband, but they stay because of the lifestyle.

Lookout Mountain offers  panoramic views of Chattanooga and the Tennessee River Valley, including areas where many of Chattanooga's shuttered factories operated.  It was also the location of the famous "Battle Above the Clouds," a battle fought during the Civil War on November 24, 1863. Union forces under Major General Joseph Hooker attacked Lookout Mountain and defeated the Confederates.

Chattanooga is a city steeped in the arts, and at the corner of Tremont Street and Frazier Avenue art meets technology. A mural painted by Chattanooga artist Kevin Bate features six founding fathers of technology: Charles Babbage, Nikola Tesla, Vannevar Bush, Alan Turing, Claude Shannon and Steve Jobs. The mural was commissioned by Woople, a Web-based e-learning company based in Chattanooga.

Local venture capital firm, Lamp Post Group has invested in Chattanooga's downtown "Innovation Zone" by buying the historic Ross Hotel, a four-story landmark at Patten Parkway and Georgia Avenue.  The firm is renovating the building to create micro-apartments designed to house budding entrepreneurs and innovators in a shared living space.

Chattanooga has become a hub for 3D printing. Startup Feetz relocated to Chattanooga from San Diego. The company prints custom shoes and has already brought in $1.25 million in seed funding led by Silicon Valley-based venture capital firm Khosla Ventures.

Feetz founders call themselves the "digital cobbler."  The company is using 3D printing to customize the manufacturing of shoes. Using a mobile app, customers take pictures of their feet and send them to Feetz, which uses the measurements to 3D print the shoe. Styles and materials are limited today, but the possibilities for the future are limitless, said CEO and founder Lucy Beard.

Branch Technology hopes its freeform 3D printing technology will disrupt the $8.5 trillion worldwide construction industry. The company, whose founder relocated from Alabama to Chattanooga, participated in Chattanooga’s startup accelerator program GigTank. And at this year’s event, the company unveiled its first prototypes of 3D printed walls using the world’s largest 3D printer, which stands 25 feet wide by 58 feet long.

Branch’s founder Platt Boyd, an architect by training, said he was inspired by the way nature builds. By creating a skeleton or scaffolding of the design using 3D printing, Branch can fill in the empty spaces with traditional construction materials to create a wall of almost any shape. The company showed off its new technology and prototypes for the first time at the GigTank Demo Day in Chattanooga in July.

One of the core advantages of 3D printing is that it allows for customization and complexity, according to Branch. This 3D printed scaffold made out of lightweight plastic acts as the base for an interior wall that otherwise would have been sculpted by a skilled artisan.

This is one of the first prototypes of an interior wall created by Branch. Its base is similar to the scaffold in the previous photo. The company says its purpose is to show designers what is possible using this 3D printing technology “when geometric freedom is applied to construction.”