Grand Prix tennis circuit
The ITF Grand Prix Circuit was a professional tennis tour for male players founded in 1970 as the Grand Prix Tennis Circuit it was administered by the International Tennis Federation (ITF) and ran annually until 1989 when it and the rival WCT Circuit were replaced by a single worldwide ATP Tour. The women's tour the ILTF Women's International Grand Prix Circuit ran from 1971 to 1976.
Source: Wikipedia — Grand Prix tennis circuit (CC BY-SA 4.0)