Alaska's route system spans more than 92 cities in the United States, Canada, and Mexico. The airline operated charter flights to the Russian Far East starting in the late 1960s, and was known for the 1988 Friendship Flight to Provideniya that broke the old Soviet border.[citation needed] The airline began scheduled operations to the Russian Far East in 1991 following the break up of the Soviet Union, but suspended the service in 1998 following the Russian financial crisis. The airline flew MD-80 aircraft on these routes.