… OK, maybe not the largest in the entire world — (that honor belongs to the U.S. Military’s 80-by-120-foot Moffett Field built in the 1940’s), but it is the world’s largest one dedicated to automobile testing. It’s the General Motors Aerodynamic Laboratory in Warren, Michigan. Its 43-foot diameter wind turbine is capable of reaching wind speeds of up to a whopping 415 miles per hour, but is capped to 138 miles per hour in the testing zone. Even though most aerodynamic testing is done through software systems today, GM’s massive wind tunnel still proves valuable for providing physical confirmation of computer simulations.