ATLANTA — There was a time in the 1960s when Underground Atlanta, a 12-acre complex of viaducts and storefronts in the heart of downtown, was billed as this city’s answer to Bourbon Street. In the 1980s, it was reimagined as a tourist-friendly “festival marketplace” full of novelty retailers angling to attract out-of-town conventioneers. When that idea faltered, there was talk of turning it into a casino.

Today, after languishing for years as a tacky, costly hole in the center of the city, Underground is due for its next major makeover, one based on a radical concept for this sprawl-loving metropolis: People might actually want to live downtown.

By September, a South Carolina development company is expected to complete its $25.8 million purchase of Underground. Plans discussed by the company, WRS, call for adding roughly 900 apartments and a supermarket, and renovating the cavernous below-street-level mall, home to a row of shuttered nightclubs and vendors hawking hip-hop CDs, $10 jeans and rhinestone cellphone cases.

These days, “there’s not really much attracting people to Underground,” said Tre Tate, an out-of-work actor who was hanging out there recently.