In 1914, he travelled to Papua (in what would later become Papua New Guinea), where he conducted fieldwork at Mailu Island and then, more famously, in the Trobriand Islands. The ethnographic collection he made on the Trobriand Islands is now held by the British Museum. On his most famous trip to the area, he became stranded due to the outbreak of World War I. Malinowski was not allowed to return to Europe from the British-controlled region because, though Polish by ethnicity, he was a subject of Austria-Hungary. Australian authorities gave him the opportunity of conducting research in Melanesia, an opportunity he happily embraced. It was during this period that he conducted his fieldwork on the Kula ring and advanced the practice of participant observation, which remains the hallmark of ethnographic research today.