Records of more than 100,000 British prisoners of war captured during World War II are being published online.
The ancestry.co.uk lists, accessible for a fee, were compiled by the German military authorities under the 1929 Geneva Convention.
They contain details of British and Commonwealth personnel held in Germany, Austria and Poland in WWII.
The records have only now been made public and the website claims to be the first in the world to publish them.
The collection is expected to be a valuable resource to family historians trying to trace relatives captured in the war.
Daniel Jones, of ancestry.co.uk, said: "The unwavering spirit of British prisoners of war was astounding - with many trying to escape their captors at every opportunity in order to rejoin the war effort.
Home-run: Term coined by POWs to describe a successful escapee who made it back to his home country
MI9: Secret British government unit set up to instigate and assist POW escapes
Escape entitlement: Under international law, POWs were entitled to try to escape. However the German Kugel Erlass (bullet decree) meant the Germans could shoot those who did
Stalag 383: Contender for best POW camp. Some accounts say German guards left running of camp to British prisoners. Pets were allowed
Stalag IX-B: Contender for worst camp. Prisoners slept on floor. Barracks for 160 people had one tap and the toilet was a hole in the ground
"This collection of records will be a way for people to find out more about the heroes in their family."
Most WWII records are still not available for public inspection as military personnel records are not transferred to the National Archives until at least 75 years have passed.
Prisoners named in the collection include Desmond Wilkinson Llewelyn, the actor most famous for playing "Q" in James Bond films.
The former lieutenant with the Royal Welch Fusiliers was captured in 1940 and held in a German prison for five years.
Others detailed in the lists include George Henry Hubert Lascelles, the 7th Earl of Harewood, then seventh in line to the throne.
Viscount Harewood was held at Colditz Castle from 1944 until the end of the war.
Escape from Colditz
The records shed light not only on where British prisoners were held but also attempts at escape.
Serial escaper JRE (Jock) Hamilton Baillie managed to get beyond the perimeters of five separate German prison camps.
He was eventually sent to Colditz, which he attempted to flee from dressed in a black burglar's cat suit.
The website is also publishing the UK Army Roll of Honour for 1939 to 1945.
It includes the records of all British Army personnel killed in action during World War II, including those who died of natural causes, wounds and diseases.
More than 170,000 names of servicemen are listed, as well as their rank, date of death, service number, birth place and residence.