 The last ever public performance by the opera singer, Maria Callas, was in Sapporo at the Hokkaido Koseinenkin Kaikan on 11 November 1974.The Sapporo Municipal Subway was expanded when the Tōzai line started operation in 1976, and the Tōhō line was opened in 1988.In 1989, Atsubetsu-ku and Teine-ku were separated from Shiroishi-ku and Nishi-ku.