During this period, the Hudson's Bay Company built several factories (forts and trading posts) along the coast at the mouth of the major rivers (such as Fort Severn, Ontario; York Factory, Churchill, Manitoba and the Prince of Wales Fort). The strategic locations were bases for inland exploration. More importantly, they were trading posts with the indigenous peoples who came to them with furs from their trapping season. The HBC shipped the furs to Europe and continued to use some of these posts well into the 20th century.