What country were both the 2015 and 2017 World Junior Ice Hockey Championships held?
2017 World Junior Ice Hockey Championships:  The main tournament was co-hosted in Montreal, Quebec and Toronto, Ontario, in Canada. 2015 World Junior Ice Hockey Championships: The 2015 IIHF World Junior Championships was the 39th edition of World Junior Ice Hockey Championship, played from December 26, 2014 to January 5, 2015.
i don't know