5 things to know on Wednesday, Dec. 21, 2016

5 issues to know: Prime Minister Trudeau visits Calgary to debate pipelines; an explosion at a fireworks market in Mexico kills dozens; Canada and the U.S. ban offshore oil and fuel licensing within the Arctic; Trudeau says he'll defend Canadian pursuits if Donald Trump goes too far; and the one survivor of a 1986 roller-coaster crash in Edmonton needs a memorial constructed for many who died within the crash.