D-09, a former active minuteman missile silo, has been converted into a open museum, on the prairie outside of Wall, South Dakota. The museum also includes a command center, and a information center near the interior exit on I-90, Delta-09 was one of over 100 silos, set up in western South Dakota, protecting the US from the Soviet Union. The missiles were never fired fir a wartime threat, but a few missiles would be tested out in California. The only silos left active are in North Dakota, Nebraska, Wyoming and Montana.