A more or less cool term used by more or less cool people, to refer to their hometown, to the town they study in (->unisg.ch), or the town they just like for whatever reason.
THAT TOWN IS "ST. GALLEN" (SANKT GALLEN) IN THE NORTHEAST OF SWITZERLAND, capital of the Canton by the same name.
A term often used on posters and flyers for clubbing in that town.
Didi: Ey, oylà. wa machsch da Wuchänänd? Blibsch in Züri?
Steff: Nei, Mann. I gang hei uf Saint City.
Didi: "Hey - Whatcha doin this weekend? You staying in Zurich?"
Steff: "No, man. I'm going home to St. Gallen."