The Koppers Corporation helped build its (*) coke ovens.  
A huge percentage of this city's workers are employed by the privately owned MMK.  Bitterly cold winds rip through the superblocks of this non-German city designed by Ernst May.  In February, 2016 Leonardo DiCaprio reposted on Instagram a picture of how badly polluted this city was, not knowing the picture was 22 years old.  Hundreds of employees of Cleveland's Arthur G. McKee Company helped build this closed city, and the Freyn Engineering Company was hired to design a railroad that would connect it to Kuznetsk, a thousand miles away.  This city was modeled on Gary, Indiana.  The Koppers Corporation helped build its (*) coke ovens.  Migrating birds avoided flying near this city's nearby mountain, which had so much iron ore it caused compasses to malfunction.  By 1936, this city was producing some 3.7 million tons of iron and steel.  For 10 points, name this Soviet "city of metal".
A huge percentage of this city's workers are employed by the privately owned MMK.  
Magnitogorsk