Ruhleben internment camp was a civilian detention camp during World War I. It was located in Ruhleben, a former Vorwerk manor 10 km (6.2 mi) to the west of Berlin, now split between the districts of Spandau and Charlottenburg-Wilmersdorf. The camp was originally a harness racing track laid out north of the Berlin-Hamburg Railway line in 1908.
The camp detainees included male citizens of the Allied Powers living, studying, working or on holiday in Germany at the outbreak of World War I. They also included the crews of several civilian ships stranded in German harbours or captured at sea. There were also quite a number of fishermen captured from trawlers which were sunk in the North Sea in the first days of the war - these were mainly men from Hull, Grimsby and Boston. The camp varied between 4,000 and 5,500 prisoners, most of them British. Life in the camp has been described in several books and essays subsequently written by detainees. These include To Ruhleben – And Back by Geoffrey Pyke, who successfully escaped from the camp in 1915, and Life in Ruhleben, 1914–1918 by Frederick Keel. Quarters were cramped; the stable blocks averaged 27 stalls each housing six men; the stable block lofts each housed about 200 men.
The German authorities adhered to the Geneva Convention and allowed the camp detainees to administer their own internal affairs. Gradually, a mini-society evolved in the camp. Letters, books, sports equipment and a printing press were all allowed into the camp and the detainees organised their own police force, magazine, library and postal service. The latter, known as the Ruhleben Express Delivery, was organised by Albert Kamps and began operating in July 1915. Soon it was handling over 6,000 pieces of mail per month and 16 different postage stamps, which have since become collectors items, were issued. In April 1916 however the German postal authorities declared the service illegal and it ceased operating. In addition, a number of independent businesses, including a casino, also developed within the camp.