Ruan Transportation built the Ruan Center at 666 Grand Avenue, the skyscraper you are facing, and completed it in 1975. From here you can see why locals call it the "rusty skyscraper"—its exterior skin is Cor-Ten steel that sheds rust, made up of 1,600 US tons of that cladding. The tower rises 459 ft (140 m) and once held the title of Iowa's tallest building until 801 Grand eclipsed it in 1991. Its frame contains 4,700 tons of structural steel, a reminder of the scale of its construction.
Most of the floors house offices and the building links into Des Moines' skywalk system, making it part of how the city moves. On the 33rd and 34th floors is the Des Moines Club, a private members-only restaurant. The Ruan Center was named one of the 50 Most Significant Iowa Buildings of the 20th Century by the Iowa chapter of the American Institute of Architects. Alongside its neighbor, Two Ruan Center—also known as the Carriers Building, completed in 1982—it was listed on the National Register of Historic Places in 2025. Notice the rust-streaked Cor-Ten skin rising 459 feet, tied into the city by its skywalk connections.