Winston Churchill called it a "miracle of deliverance".
Three hundred and forty thousand allied soldiers were rescued from the beaches of Dunkirk by a flotilla of boats of all sizes between 28 May and 4 June 1940, enabling them to fight another day.
The escape of soldiers from the Royal Ulster Rifles was as miraculous as any in those days.
The regiment formed part of the rearguard tasked with buying time for the soldiers trapped on the beach.
However, at the last minute the Rifles' order to fight to the last man was overturned and they had the chance to try to make it to the beaches and hope for evacuation.
The drama and heroism of the evacuation - Operation Dynamo - is examined in historian Dan Snow's documentary Little Ships, on BBC2 on Thursday.
Mr Snow retraces the role of the Royal Ulster Rifles through the war diary of one member of the regiment in the documentary.
They were among the last soldiers to leave Dunkirk, with many of them making it onto the ships and safety.
However, the historian also visits a French cemetery where eight of the RUR are buried alongside each other.
He also meets with veterans from other British regiments who owe their lives to the little ships which braved the channel to rescue them.
They tell him what it was like to await rescue while under fire and bombardment from the Luftwaffe after an exhausting march to the beaches.
Their ordeal wasn't over then, as those who were rescued still had to endure the treacherous journey back to England.
Little Ships is on BBC2 on Thursday, 3 June at 9.30pm and will be shown again on Saturday, 5 June at 7.25pm on BBC Two.
The programme was made by BBC Northern Ireland for BBC Two.