The U.S. Marine Corps' Combat Development Command, which develops strategies for U.S. Marine combat and makes up most of the community of over 12,000 military and civilian personnel (including families), is based here. It has a budget of around $300 million and is the home of the Marine Corps Officer Candidates School. The Marine Corps Research Center at Quantico pursues equipment research and development, especially telecommunications, for the Marine Corps. The Marine Corps Brig, a military prison, was also located at Quantico, until its closure on 31 December 2011 and its subsequent demolition.