Columbia Down Under offers a peek at the past.

The average pedestrian out for a late autumn stroll downtown likely has no idea what lies beneath the stately building at the corner of Main and Washington streets.

The first and second floors of the Arcade Mall, built in 1912, rehabilitated in 1971 and in the final stages of a years-long renovation that began when its current owners bought the building in 2015, gleam in the sun. Snowy white cornice molding and second-floor columns are draped with holiday greens, and customers file in and out of Indah Coffee, Swanson's Deli and His and Her Tailoring, most of them oblivious to a whole other world under their feet.

A clue lies in the elevator tucked into the crook of the building where the tiled hallway makes a left turn toward Washington Street and the Blue Sky Gallery. Enter that elevator, press a button marked B, turn an access key and step out into the building's basement and back in time.

In 1972, Columbia Down Under, the brainchild of three area businessmen, opened its subterranean doors. A mix of nightclubs and restaurants with an old-timey photo booth and a liquor store thrown in, the seven venues tucked into now-dark corners draped in the occasional cobweb, were once the quirky heart of downtown Columbia.

"From all accounts, it was a really fun place," said John Sherrer, Historic Columbia's director of cultural resources. "It captured people's imagination, and it still does."

The Arcade Mall is celebrating years of renovations with a grand reopening ceremony today, though the future of Down Under remains up in the air.

"The ultimate goal and desire is to reutilize that space in some way," said Brad Shell, one of three managing members of Arcade Mall ownership group DownUnder Columbia LLC. "The trick with that is going to be how can you best reutilize it, and what is it going to cost and is it going to be worth it. The short answer is that we plan on using it, but we're just not quite sure what that is going to look like."

Historic Columbia, which became involved with Arcade Mall renovations and preservation efforts eight years ago, recently provided the public with a glimpse of the goings-on of decades gone by. The organization, which has also hosted one of its periodic behind-the-scenes tours of historic properties at the venue, kicked off its fall tour season with "Stayin' Alive on Main Street," which threw open the Down Under doors to a crowd decked out in its finest 70s threads.

Guest meandered through what was once the Trolley...