The British Special Air Service (SAS) is a special forces unit of the British Army, known for its expertise in counter-terrorism, hostage rescue, and covert reconnaissance. Established in 1941 during World War II, the SAS has a reputation for rigorous training and operational effectiveness, often working in small teams to carry out complex missions. The SAS is part of the United Kingdom Special Forces and operates under the Ministry of Defence. Its members are selected from the regular army and undergo a demanding selection process, known as the SAS Selection, which tests physical endurance, mental resilience, and tactical skills.