Editing Open Polar Sea (section)

==History==
The theory that the North Pole region might be a practical sea route goes back to at least the 16th century, when it was suggested by English cartographer [[Robert Thorne (merchant)|Robert Thorne]] (1492-1532).<ref name="CG">[https://www.brown.edu/Facilities/John_Carter_Brown_Library/exhibitions/cartographic/pages/unger.html Cartographic conversation - Brown University]</ref> The explorers [[William Barents]] and [[Henry Hudson]] also believed in the Open Polar Sea. For a time, the theory was put aside because of the practical experience of navigators who encountered impenetrable ice as they went north.

However, the idea was revived again in the mid-19th century by theoretical geographers, such as [[Matthew F. Maury]] and [[August Petermann]]. At the time, interest in polar exploration was high because of the search for [[John Franklin]]'s missing expedition, and many would-be polar explorers took up the theory, including [[Elisha Kent Kane]], Dr. [[Isaac Israel Hayes]], and [[George Washington De Long]].

It was believed that once a ship broke through the regions of thick ice that had stopped previous explorers, a temperate sea would be found beyond it.