When Dave Matthews Band Caravan comes through Chicago Friday, the concert’s musicians will be playing at a site with a lot of history.

The three-day festival features 39 bands curated by DMB, who will headline the show each night. The tour’s first stop in Atlantic City in June drew an estimated 70,000 fans, and Jerry Mickleson, cofounder of Chicago-based concert promoter Jam Productions, which is producing the Chicago stop of the tour with Live Nation/Ticketmaster, says he expects the Chicago show to be just behind Lollapalooza in terms of attendance. According to the Chicago Sun-Times, Lollapalooza attracted 240,000 attendees in 2010, or 80,000 each of the three days.

They’ve chosen an unorthodox location for the show, further afield than Lollapalooza’s Grant Park or Pitchfork Festival’s Union Park. The land they’ve found is overgrown and somewhat hidden, on a scale that’s hard to imagine.

The nearly 600-acre parcel runs along the lake between 79^th St. and the Calumet River. Who knew there was this much empty land within city limits?

Mickelson, for one. He grew up on the North Side but drove past the site regularly as he made his way to his grandmother’s cottage in the Indiana Dunes. “I would go down the street before they put up the fences and marvel at how beautiful it was,” Mickelson says. “I always had it in the back of my mind that I’d like to use it as a concert site.”

So what is this place?

This site was once home to a giant steel mill — U.S. Steel’s South Works facility. Built in 1880 and strategically located at the mouth of the Calumet River, South Works would become the third biggest steel mill in the world by the time it turned 75.

During its roughly hundred-year lifespan South Works made I-beams and angle bars for building and bridge construction. They made the kind of large steel girders used in skyscrapers, including (together with U.S. Steel’s Gary Works facility just over the border in Indiana) 42,000 tons of steel used to erect the Hancock building. At its peak South Works employed nearly 20,000 workers, most of whom lived in surrounding South Side neighborhoods.

You wouldn’t know it now. The plant closed in 1992, and most of the signs of its industrial history are gone.

But there are remnants. Case in point, the ore walls.

The ore walls run parallel to what would have been the docks right on the water. Now, they look like strange monoliths or ruins from some ancient civilization. Really they’re all that’s left of the facilities used to store the raw iron ore shipped into the steel plant.

The site was once considered a brownfield, contaminated by more than 100 years of heavy manufacturing. However, the site has undergone significant remediation, including a project spearheaded by the University of Illinois’ Sustainable Technology Center to relocate over 900 tons of reclaimed topsoil from the bottom of Lake Peoria as part of their Mud to Parks program. The Illinois EPA has certified that the site is now suitable for residential and commercial redevelopment.

Still, there are significant changes forthcoming that, if executed, would transform this portion of Chicago’s South Side. U.S. Steel’s Real Estate Division has plans to co-develop the site with Chicago-based McCaffery Interests, which has also developed sites in Chicago at 669 N. Michigan Ave. and in River North.

The development, christened Chicago Lakeside, would be massive. Phase 1, scheduled to break ground in late 2012, calls for 840,000 square feet of retail, 250 residential rental units, 136 townhomes, and three high-rise towers.  Future phases include plans for an additional 12,500 residential units, 16,600,000 square feet of commercial space, a new harbor, and an indoor cycling facility. (Construction has already begun on a temporary outdoor cycling track, which is scheduled to open later this summer.) In total, McCaffery says they plan to invest nearly $4 billion into the site.

WBEZ’s Kate Dries and Meghan Power will be at the Dave Matthews Band Caravan this weekend, looking into the relationship between the event and the surrounding neighborhood. They’ll have photos of the site as it looks revamped for the show and other coverage next week.

Historic photos courtesy of U.S. Steel.