DEVGRU soldier with his face obscured for safety reasons

Secrecy is quite often the biggest advantage that you can have at your disposal in a military situation. If you think about it in relatable terms, taking your time and planning in a skirmish is quite often a better approach than running in Gung-ho, airsoft guns blazing and getting (figuratively) cut to pieces!

Secret military units have been around, and although the respective military that each unit belonged to have admitted that they may have existed at some point, a lot of their missions were (or still are) classified.

Below, we have taken a look at 6 of the most secret units in history, and tried to piece together some of their backstory from the limited information available:

The OSS

Formed in 1942, the Office of Strategic Services was created with the very broad mission of collecting and analysing strategic information, whilst conducting “special operations” that were not assigned to other agencies.

Since there were few agencies which had special operators in World War II, this gave the OSS a pretty free reign. Under command of Col. William “Wild Bill” Donovan, the tiny agency smuggled weapons and spies, conducted raids, collected intelligence and supported resistance groups in Axis territory. They were even the first unit in U.S. history to deploy a sea, air and land commando (otherwise known as a SEAL).

7781 Army Unit/39th Special Forces Operational Detachment

Operating out of Berlin from 1956 to 1984, this group of green berets had a number of different names during their history, but their goal was always the same. They worked to keep West Berlin safe from communist invasions, but were also equipped to provoke resistance should the city be taken over.

In true James Bond style, the unit were trained in spy craft skills and equipped with gadgets such as C4-filled coal and cigarette lighter guns.

6493rd Test Squadron/6594th Test Group

These Air Force units existed from 1958 to 1986 and were tasked with catching “falling stars”. This means they would fly out of Hawaii to catch film canisters which fell from America’s first spy satellites. The satellites orbited the Earth, taking photographs of Soviet Russia. Once captured, they would drop their film canisters over the Pacific Ocean where the airmen would pluck them out of the sky.

The recovery process was surprisingly low-tech. A plane with a giant hook under its tail would try and catch the parachute deployed from the canister as it fell! If the planes failed to make the grab or the weather stopped them from doing so, rescue swimmers in the unit would retrieve the film from the water.

The unit recorded more than 40,000 recoveries in 27 years, and when the airmen weren’t catching the falling film from the air, they supported rescue missions near Hawaii. It was credited with 60 saves from these missions.

Delta Force/Combat Applications Group/Army Compartmented Elements

Similar to many units on the list, Delta have undergone a few name changes over the years. The formation of an elite counter-terrorism had been proposed many times in the 1970s, with Delta Force widely believed to have been formed in late 1977.

The operational history of Delta Force got off to the worst possible start with the failed Operation Eagle Claw in 1980, where the U.S. attempted to end the Iran hostage crisis by rescuing 52 embassy staff held captive at the Embassy of the United States, Tehran on 24 April 1980. So many things went wrong in the operation, it was eventually called off, which dealt a big blow to the standing of the U.S. across the world.

Since then, however, Delta has distinguished itself as a formidable unit in combat, from the invasion of Panama, to the Gulf War, to hunting Osama Bin Laden. Since the unit is still operational, many of their missions remain classified to the public.

SEAL Team 6/DEVGRU

SEAL Team 6 have been conducting combat operations since 1981, and specialise in counter terrorism, close protection missions, special reconnaissance and hostage rescue. Since 9/11, their responsibilities and budget have expanded greatly, and it is thought the unit has over 1,800 men and women serving as members.

The unit is probably most famous for the operation resulting in the death of Osama Bin Laden, as well as the rescue of Captain Phillips from Somali pirates.

Task Force 88/Task Force Black

Such is the secrecy of the military, they may or may not be the same group and they may or may not still be in operation… Both Task Force Black and Task Force 88 are names floating around the media for the unit that conducted raids against terror organisations in Iraq and Afghanistan during the height of the wars.

The unit has often been described as a joint U.S.-U.K. force made up of the best that Delta Force, SEAL Team 6, and the British SAS had to offer, although they came under some scrutiny when they were blamed for a cross-border raid into Syria. There have also been whispers recently that Task Force Black may come back into operation to battle against the threat of ISIS.