Short answers, pulled from the story.
Robert McClure discovered the Northwest Passage in 1850 while searching for John Franklin. He reached Banks Island and viewed Melville Island across McClure Strait after his ship was trapped in ice for three winters.
On the 21st of August 2007, satellite images showed the passage open to ships without needing an icebreaker. This marked the first time since records began in 1972 that the waterway was clear.
The Canadian government classifies these waters as internal waters under the United Nations Convention on the Law of the Sea. The United States claims the waters are an international strait where foreign vessels have the right of transit passage without permission.
Gray whales returned to Atlantic waters after being hunted to extinction there in the 18th century. Two bowhead whales from West Greenland and Alaska entered the passage from opposite directions in August 2010.
Five to seven distinct routes exist through these islands though not all suit large vessels. Some paths like the Fury and Hecla Strait remain closed by ice most years while others such as Peel Sound run south between Somerset Island and Prince of Wales Island.