Special Forces are the most disciplined, mission-capable and fearsome units in the world.
They undergo rigorous selection and training processes to accomplish unconventional missions beyond the means of standard military forces.
In reality, the world may never know exactly what these teams accomplished, but their public records contain enough information to earn the respect of the world.
Here, in no particular order, are ten deadly special ops units from around the world.
10. China Snow Leopard Commando Unit
Formerly known as the Snow Leopard Commando Unit, so named due to the tenacity of arctic wolves and their ability to survive in harsh conditions, this unit is a special operations unit of the People's Republic of China .
At its inception, it spent five years training in secret to conduct counter-terrorism, riot control, hijacking and bomb disposal operations during the 2008 Summer Olympics in Beijing.
They trained alongside Russian special forces units in joint counter-terrorism exercises, with the primary mission of maintaining peace and stability.
The unit prides itself on the speed and accuracy of its shooting, its strength and endurance, and its spirit of self-sacrifice. Each recruit must serve in the People's Armed Police for one to two years before undergoing physical and psychological testing.
It may be in martial arts and close combat that they excel the most, but their sniper squadron shouldn't be overlooked.
The next group made news when one of its operators drowned an ISIS terrorist in a puddle. Yeah.
9. The British Special Boat Service
"Not by force, by trickery" is the motto of the Royal Navy's Special Boat Service, one of the UK's most secretive elite military units.
The SBS is the British equivalent of the US Navy SEALs. The selection process for this elite team has a 90% failure rate and includes a grueling four-week endurance test that gets progressively more difficult and culminates in a 25-mile march for my fellow Yankees. - which must be completed in less than 20 hours.
And this is only the second stage of training.
Graduates will need to master weapons handling, jungle training, complex combat and combat survival before being officially inducted into the elite unit.
Born out of World War II, the SBS remains one of the most respected units in the world today. Since 9/11, the Special Boat Service has been deployed against Al-Qaeda, ISIS and the Taliban, as well as on rescue missions around the world, including Sierra Leone and Libya.
8. The Polish GROM
GROM is an acronym that loosely translates to "Operational Maneuver Response Group".
But, more poignantly, grom means "thunder" in Polish. It is a unit whose origins can be traced back to the exiled Polish paratroopers of World War II, known as the "Silent Unseen".
315 men - and one woman - trained for months in Britain before jumping into occupied Poland to oppose the grip of the Nazis.
In 1990, the GROM unit was organized after Operation Bridge, a mission to help Soviet Jews enter Israel.
With intelligence reports pointing to a significant Hezbollah threat in the area of operations, the creation of this elite counter-terrorism force was approved. She remained secret from the public until 1994, when she was deployed to Haiti for Operation Restore Democracy.
The GROM performs rescue operations, including hostage recovery, as well as counter-insurgency missions.
They possess extensive weaponry and medical expertise and are proficient in various military disciplines including parachuting, amphibious insertion, diving, pyrotechnics, and vehicle driving.
Whether fighting terrorists or war criminals, the GROM more than lives up to its name.
7. The Special Services Group in Pakistan
Business Insider reported that the Pakistani Special Services Group's training requires a 36-mile walk in 12 hours and a five-mile kit run in 20 minutes — if that's true... then damn goodnight.
Created to fight terrorism, extremism, and separatism, SSG training consists of grueling physical conditioning, paratrooper school, a 25-week commando course, and unarmed combat training. According to reports, only 5% of recruits complete this rigorous training.
Due to their geographical location, they are actively engaged in counter-terrorism missions.
From hotspots along the Indo-Pakistan border, to the current conflict in Afghanistan, to Operation Zarb-e-Azb, a joint military offensive targeting terrorist organizations, the SSG goes where the fire is hot.
Delta Force is the US military's elite counter-terrorism unit. It counts Rangers and Green Berets among its members, but also Navy and Air Force operators.
It has gone by many names - Special Forces Operational Detachment-Delta, Combat Applications Group, and now Army Compartmented Elements, but throughout its short history it has retained its superior ability to capture or kill high value targets, to dismantle terrorist cells and carry out covert missions in any area of operations.
Most of the missions carried out by Delta Force remain secret - and it is rare to find an official document acknowledging the unit - but one of its most notable accomplishments is Operation Red Dawn, the capture of Saddam Hussein.
A leaked recruiting video provided insight into the various Delta Force training methods, including tactical driving, vehicle abduction and assault tactics.
A testament to their accuracy, one of their final exams includes undercover operations in which members of the team play the role of the hostage while his brothers fire live ammunition at nearby targets.
The operation builds trust within the team and reminds the shooter not to touch the hostage.
5. The Intervention Group of the National Gendarmerie of France (GIGN)
The National Gendarmerie Intervention Group is one of the most combat-experienced counter-terrorism organizations in the world. Somewhere between a SWAT team and the Delta Force, the French GIGN responds to terrorist threats or domestic attacks.
The enemy has evolved, and so has the GIGN. Their mission is to get to the scene of an attack as quickly as possible, then capture or kill the attackers before they can inflict further carnage.
Their training program is notoriously brutal and lasts fourteen months - if recruits can hold out that long. A documentary crew followed a group of potential recruits and saw 120 of them reduced to 18 in two weeks. Training includes one of the best shooting schools in the world, weapons handling, skydiving lessons including HALO jumps, unarmed combat, diving, survival training and neutralization explosives.
These men are deadly, but they appreciate the discipline of shooting. Rumor has it they just got a 6-shot .357 revolver as their official sidearm - with just 6 rounds, you can be sure they're going to make every single one count.
4. The Sayeret Matkal of Israel
Also known as "Unit 269", Israel's Sayeret Matkal is a top-secret special operations brigade of near-legendary status. Since its inception in 1957, Sayeret Matkal has earned a reputation for its deep reconnaissance capabilities and counter-terrorism and hostage recovery missions.
She relies on secrecy, attacking in small numbers and in disguise, then fading away before the enemy realizes what has happened.
Perhaps one of its most notable operations was the rescue of Entebbe in 1976, when an Air France plane carrying 250 passengers from Tel Aviv to Paris was hijacked by terrorists. The non-Israeli passengers were released, but 106 hostages remained. The rescue mission took a week to plan and just over an hour to execute.
The disguised task force was flown in with Land Rovers and a Mercedes-Benz. They succeeded in infiltrating the local army, killing the terrorists and rescuing all but four of the hostages. Only one Israeli soldier was killed in the attack.
That's the problem with Sayeret Matkal - once you know he's there, you're already out of time.
3. Spain's Special Naval Warfare Force
The Spanish Naval Special Warfare Force was created in 2009 when the country merged various units of the Spanish Navy into a single combat entity. The "Fuerza" is made up of the special unit of combat divers, the special unit of explosives diffusers and the special operations unit - its main tactical predecessor.
The special operations unit was responsible for maritime counter-terrorism, combat diving, air and amphibious insertion, combat search and rescue, and ship boarding - the unit d today's elite continues the fight.
Today's elite unit continues the fight. She has a long history of using these tactics in rescuing hostages and fighting pirates.
In 2002, rana hombres supported Operation Enduring Freedom in the Indian Ocean when they stormed a North Korean ship carrying SCUD missiles to Yemen. Then, in 2011, they rescued a French hostage from Somali pirates.
And that's only public knowledge - like the other elite units on this list, most of their missions remain classified.
2. Russian Spetsnaz
The Russian Spetsnaz is shrouded in mystery, but it dates back to the Bolshevik Red Guard, a paramilitary force organized at the height of the Russian Revolution in the early 20th century. Most of its members are comparable to the US Army Rangers, but a small elite train like the Delta Force.
Their traditional training is to scout the battlefield, break enemy chains of command and supply lines, and target enemy weapons and tactical advantages, but one thing that differentiates them from American operators is their freedom to "mix and match" their weapons.
Recently, Russia has increasingly modeled its Spetsnaz after American counterparts.
To a casual observer, it might seem hard to tell them apart from each other, but at the end of the day, there's a reason Russia is trying to follow the United States.
I lied. I saved it for last.
The United States Navy SEALs are perhaps the best special operations forces in the world. The competition standard to be considered for BUD/S training is to swim 500 yards in 10:30, 79 push-ups, 79 sit-ups, 11 pull-ups, and a 1.5-mile run in 10:20. And that's just to be admitted.
Preparing to become a SEAL includes basic underwater demolition, parachute jump school and SEAL qualification training – all of which have been described as “brutal” – then they undergo another 18-month training before the deployment.
SEALs provide highly specialized and intensely challenging tactical capabilities, including direct action warfare, special reconnaissance, counterterrorism, and foreign home defense.
From the Korean War and the Vietnam War to Somalia, Operation Iraqi Freedom and Operation Enduring Freedom, Operation Inherent Resolve and, of course, the death of the international terrorist Osama bin Laden, the Navy SEALs have left their mark.