Bubeneč is a district in the north-west of Prague, located partly in Prague 6 and partly in Prague 7. The main cadastral[clarification needed] parts of Bubeneč are Císařský ostrov, Stromovka (Královská obora) and Výstaviště. 52% of Bubeneč is in Prague 7, but most of the build-up area is in Prague 6. Bubeneč was a city between 1904 and 1921 but in 1921 it was joined with Prague. The area was greatly favored by Russian immigrants in the pre-World War II era. Sparta Prague football club and their stadium Generali Arena lie on the south-eastern edge of Bubeneč. The name Bubeneč is masculine, although Czech grammar rules also allows its use as a feminine.