The northwest passage referred to

It is the maritime route that goes from the Northern Atlantic Ocean, through the Arctic Ocean and the northern waterways of the Canadian Arctic Archipelago to reach the Pacific Ocean. For centuries it has been blocked by the polar ice cap that covers the sea of the region all year round but due to global warming, the ice cap has thinned to levels that make possible transit during the summer, which makes it interesting as a shipping commercial route to and from Asia.