 In early 1914 , the German government sent Detzner to explore and chart the interior of Kaiser @-@ Wilhelmsland , the imperial protectorate on the island of New Guinea . When World War I broke out in Europe , he was well into the interior and without radio contact . He refused to surrender to Australian troops when they occupied German New Guinea , concealing himself in the jungle with a band of approximately 20 soldiers . For four years , Detzner and his troops provocatively marched through the bush , singing " Watch on the Rhine " and flying the German Imperial flag . He led at least one expedition from the Huon Peninsula to the north coast , and a second by a mountain route , to attempt an escape to the neutral Dutch colony to the west . He explored areas of the New Guinean interior formerly unseen by Europeans and surrendered in full dress uniform , flying the Imperial flag , to Australian forces in January 1919 . 
