Seattle's professional sports history began at the start of the 20th century with the PCHA's Seattle Metropolitans, which in 1917 became the first American hockey team to win the Stanley Cup. Seattle was also home to a previous Major League Baseball franchise in 1969: the Seattle Pilots. The Pilots relocated to Milwaukee, Wisconsin and became the Milwaukee Brewers for the 1970 season. From 1967 to 2008 Seattle was also home to an National Basketball Association (NBA) franchise: the Seattle SuperSonics, who were the 1978–79 NBA champions. The SuperSonics relocated to Oklahoma City, Oklahoma and became the Oklahoma City Thunder for the 2008–09 season.
In what year did the Seattle Metropolitans win the Stanley Cup? (If the question is unanswerable, say "unanswerable")
1917