The Central Powers captured 7.000.000 Allied prisoners of war during the Great War. Most of them (2.800.000) became wards of the German state during massive offensives. The German Army established and maintained 165 parent prison camps (Stammlagern) where Allied war prisoners were transported by rail.
Stammlagern included barracks each of them accommodated about 250 prisoners. There were wood stoves to heat the dormitories and most had electric lighting. Barracks were equipped barracks with running water for washing and drinking. Prison camps also had a common bathhouse, which included showers and bath tubs, and a common laundry building. Each prisoner had his own bunk and received a straw sack, to serve as a mattress, and a blanket. Safety was a critical concern in prison camps and fire was the greatest hazard. A fire in a crowded barrack could kill hundreds of men. Prisoners were not permitted to smoke or cook inside their barracks and most of the support buildings. the Germans adopted a policy of utilizing Allied POW’s in agriculture, industry, raw material extraction (especially coal, iron, and salt), state projects (like flood control and moor reclamation), and government projects (such as railroad work)
Austrian prisons were much larger in size than German Stammlagern, holding from 40,000 to almost 100,000 prisoners, in order to obtain economies of scale. The Austrians incarcerated over 1.000.000 Allied prisoners of war (300,000 Italian prisoners of war as a result of the Battle of Caporetto in October 1917)
The Bulgarians captured their large group of prisoners in October 1915 during the invasion of Serbia as well as small numbers of British, French, Italian, and Greek POW during the Macedonian Front. They established their largest prison camps in Sofia, Sliven, Philippopolis, and Haskovo, as well as some military prison camps in occupied Serbia, including Nish and Struga. the Bulgarians assigned Allied prisoners to labor detachments, especially in agricultural and transportation work, to help support the war economy and reduce the burden these POW’s placed on national resources
Opposite to Allied POW experiences in World War II, Entente prisoners received far better treatment and care in the Great War.
Prisoners facing an interminable period of incarceration often fell victim to depression or "barbed-wire disease." This depression resulted from the daily monotony of camp life and the stress of indefinite confinement. German and Austro-Hungarian prison camp officials permitted and supported efforts by POW's to provide a wide range of musical and theatrical performances to entertain inmates. These theaters became one of the most popular buildings in prison camps in which audiences consisted of war prisoners and German officers and guards. Prisoners spent much of their free time playing cards and board games. Other prisoners engaged in hobbies such as wood-working, modeling, and carving and produced quality works. Reading was another important pastime for POW's. German authorities allowed POW's to publish their own newspapers and magazines which covered camp news, poetry, humor, history, science, sports news, and other topics of interest. Music was especially important in helping prisoners cope with incarceration. The POW’s obtained musical instruments, through purchase or through camp construction, and formed bands and orchestras. German and Austro-Hungarian authorities provided war prisoners with access to playing fields, both inside and outside the camp compound. Sports not only kept the participants in shape, it provided entertainment for spectators. Prison camp authorities allowed the POW's to establish chapels or synagogues inside buildings or construct churches within the camp compound. Officials allowed POW's in camps without places of worship to visit churches outside the prison facility if they gave their parole… Religious observation was important in prison camps during funerals and church holidays. Deaths were inevitable in prison camps due to wounds, sickness, and malnutrition. German and Austro-Hungarian authorities established cemeteries near prison camps where dead POW's could be interned. Artisans in the camps often produced stone memorials to their fallen comrades Christmas and Easter were times of acute depression and home sicknesses since POW's were isolated from their homes and families. Special religious services were held during these holidays which included the decoration of churches in the spirit of the season. In terms of medical care, the Germans and Austro-Hungarians equipped prison camps with lazarettes (hospital wards), infirmaries, dispensaries, quarantine stations, and apothecaries to care for wounded and sick Allied prisoners. Captured Allied doctors joined German and Dual Monarchy medical staffs in providing care for infirm prisoners The prevention of the transmission of infectious diseases in crowded prison camps became a major priority for German and Austro-Hungarian authorities during the Great War. The potential outbreak of epidemics in Austro-Hungarian prison camps was particularly high due to the poor health conditions of Russian, Serbian, and Romanian prisoners of war which made up the majority of the populations of prison camps. When POW’s arrived at prison camps, they immediately reported for a medical inspection. German or Dual Monarchy and Allied doctors examined all of the incoming inmates to determine their health condition. POW's suspected of carrying contagious diseases were assigned immediately to quarantine camps outside the main camp for a period of 40 days and kept away from the general camp population. Prisoners who passed the medical exam proceeded to the disinfection station. Even after the disinfection process, the Germans maintained tight sanitation regulations in prison camps. Prisoners bathed or showered on a weekly basis and had access to barbers The issue of prisoner correspondence was addressed in the Hague Agreements. Under international law, prisoners could send two letters of two pages every month and receive an unlimited supply of correspondence. POW mail traveled internationally free of charge. Translators had to censor all mail exchanged by prisoners to make sure that prisoners did not pass along intelligence and families and friends did not provide contraband information. This process required large staffs to process mail and censors had considerable freedom to ban correspondence (from: Western Michigan University - First World War Central Power Prison Camps - Kenneth Steuer)