It's a wheel thing

Ferrari Friday … vantage point

Alberto Ascari racing through the crowds in his Ferrari 375 at Pedralbes during the 1951 Spanish Grand Prix

2 Grand Prix would beheld at Pedralbes, a city circuit in Barcelona, the 2nd one in 1954
it wouldn’t be until 1968 that the next official Spanish Grand Prix would be organised, held at Jarama, near Madrid