The huge building rising above Lake Michigan was built as an icon of the Industrial age, but has been transformed into a lynchpin of the 21st century digital economy. 350 East Cermak Road in Chicago is a historic landmark that serves as a modern information fortress. Its halls are defined by elaborate Gothic architecture dating to its 1912 construction. But open any door - most of which are secured by keycards or biometric security - and you're likely to walk into a data center managing high-value bits pulsing through the heart of the Internet economy.

The 1.1 million square foot facility is owned by Digital Realty Trust, the nation's largest operator of data center facilities. Originally developed by the R.R. Donnelley Co. to house the printing presses for the Yellow Book and Sears Catalog, 350 East Cermak was converted to telecom use by the Carlyle Group in 1999, and owned by El Paso Global Networks from 2001-2005. In May 2005 Digital Realty bought the building, then known as the Lakeside Technology Center, for $140 million.

Today it is one of the world's largest carrier hotels and the nerve center for Chicago's commodity markets, housing data centers for financial firms attracted by the wealth of peering and connectivity providers among the 70 tenants.

More than 90 percent of the building is occupied. In November, Digital Realty Trust negotiated an agreement to reclaim 120,000 square feet of unused space from Qwest, which is now being redeveloped as Turn-Key Datacenter space, providing additional inventory in a high-demand market.

The building features 14-foot ceilings and can support weight loads of 250 pounds a square foot, a design feature that originally allowed Donnelley to store huge reams of newsprint on upper floors. These were lowered to the printing press floor through a series of 21 vertical shafts, which now serve as risers for fiber and power cabling. The floor loads allow providers to house heavy equipment, such as transformers, on upper floors.

The industrial strength infrastructure includes four fiber vaults and three electric power feeds, which provide the building with more than 100 megawatts of power. 350 East Cermak is currently the second-largest power customer for Commonwealth Edison, trailing only Chicago's O'Hare Airport. Grid power is supported by more than 50 generators throughout the building, which are fueled by multiple 30,000 gallon tanks of diesel fuel.

One of the most distinctive features of the facility is its cooling system, which is supported by an 8.5 million gallon tank of a refrigerated brine-like liquid. The huge tank serves as thermal energy storage for the Metropolitan Pier and Exposition Authority (MPEA), including the nearby McCormick Place Exposition Center and Hyatt Regency Hotel as well as 350 East Cermak. Thermal energy storage can reduce costs by running chillers during off-peak hours when power rates are cheaper.

The Trigen facility chills the liquid to 32 degrees and pumps it to the nearby buildings, which use it in a heat exchanger system to support their on-site cooling infrastructure. For Digital Realty, that includes a water-and-glycol system and enormous air handlers that deliver chilled air to tenants. (See CSELive for a detailed description of the MPEA/Trigen system).

For all its modern infrastructure, the building is known for its architecture, especially the Memorial Library, with its huge cathedral ceiling and bookshelves. The room was featured in the 2006 Will Ferrell film "Stranger Than Fiction."

350 East Cermak retains the architectural vision of T.E. Donnelley, who saw the facility as a bridge between the worlds of art and commerce."I want a building that will reflect the fact that the printing business is an art as well as a trade," Donnelley instructed architect Howard Von Doren Shaw in 1912. "We are trying to make the whole building dignified and beautiful - something that will be beautiful not only today, but one hundred years from now."