General Motors yesterday recognized the 100-year anniversary of the oldest test site in the automotive industry, the Milford Proving Ground. 

After a century in operation, the proving ground, strategically placed between GM's hubs in Flint, Detroit, Lansing and Pontiac, Michigan, still plays a crucial role in GM's testing and R&D operations. 

GM bought the 1,125-acre site in 1923 for about $100,000. Originally called "The Bluff," the site provided 5.5 miles of test roads on rugged terrain with 267 feet of elevation change. The grounds now have more than 4,000 acres and 150 miles of roads. 

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