Five thousand years of military history. The best elite unites that have fought across the globe. Their story told by acclaimed adventurer and ex-SAS officer Ranulph Fiennes. 

Throughout human history the art of warfare has evolved into many forms across numerous theatres, gradually becoming more sophisticated and strategised as the centuries have progressed. From the Spartans of ancient Greece with their code of valour fighting to the last man to the US Navy SEALs who operate using the latest technology of the 21st century.

Across the vast array of military campaigns and battles one can see that the majority of organised armies have been comprised of enlisted men who would have their basic training. As time progressed all countries saw the need to also have units that were the 'best of the best', that would be fit and strong and enjoy the best training and weaponry available. These elite units would be deployed to achieve extremely tough objectives, to guard a valuable fortification or person or to act as a barrier in a crisis. The term 'elite' is the ultimate accolade and one to which only the toughest would try to aspire to: undergoing intensive and harsh physical training and ultimately sacrificing themselves for the given objective.

Ranulph Fiennes himself served in Britain's toughest formation, the SAS. Since his military days he has won acclaim as an extraordinary brave and resourceful Arctic adventurer. It is fitting that he now looks back across 5,000 years of military history to pinpoint and celebrate the best elite units that served and fought across the globe.