They joined up together, fought together and often died together.
Pictures and records of members of so-called Pals Battalions formed during the First World War have been released online to help their descendants piece together their war service.
The recruits, so raw in some pictures that they have yet to be given uniforms, were amongst those who volunteered in their thousands in 1914 to serve King and Country in the fields of Flanders. Many would never return.
Website findmypast.co.uk has released details including information from medal index cards, service records and other contemporary sources to provide what it claims is the most complete picture of the Pals Battalions to date.
In many cases, large numbers of young men all working for the same company joined up and fought together. They would later be slaughtered in their thousands, most notably on the Somme.
Paul Nixon, military historian at findmypast.co.uk, said: "Having such an extensive set of records available online is a huge benefit for anyone wanting to discover if their grandfather or great-grandfather volunteered alongside colleagues and neighbours during the First World War, especially after the terrible casualties that many of the Pals Battalions suffered."
Pals Battalions were raised early on in the war, when it became clear that the professional but comparatively small British Army was massively outnumbered.
They were the men who were inspired by the famously moustachioed Lord Kitchener's "Your Country Needs You" campaign. The volunteer drive started with the Stockbroker's Battalion - officially the 10th Battalion, Royal Fusiliers - made up of officer-class stockbrokers and office boys from City firms.
Dozens of other battalions were raised from across the UK, including industrial cities in the Midlands, north of England, Scotland and Wales.
The archive includes photographs, including several of different battalions of the Manchester Pals (The Manchester Regiment) and what is believed to be a composite created of all the men from one firm in the city, JT Smith & JE Jones Ltd.
Others shed light on units which suffered heavy losses on the Somme.
They include the Southdowns Battalions, (11th, 12th and 13th Battalions, Royal Sussex Regiment), which undertook a diversionary raid on June 30, 1916, to distract the Germans from the main attack. According to Findmypast, they lost more than 300 men, including six sets of brothers, and more than 1,000 were wounded.
The pictures include several of Sergeant Frank Worley, who was servant to the war poet Edmund Blunden and also worked as a fishmonger. They include a shot taken during the 1950s during a pilgrimage to France by members of the unit.
Two other units, the 1st and 2nd Bradford Pals (West Yorkshire Regiment) were almost wiped out on the first day of the battle of the Somme, July 1, 1916. They suffered 1,770 casualties out of 2,000 soldiers.
Findmypast has published records from 32 of the 144 Pals Battalions, including from Birmingham, Bradford, Edinburgh, Glasgow, Liverpool, Manchester, Oldham, Salford, Swansea and London.