How many grand prix won Senna?

The Monaco Grand Prix predates the organised World Championships; the Principality's first Grand Prix race was organised in 1929 by Antony Noghes, under the auspices of Prince Louis II through the "Automobile Club de Monaco" (A.C.M.). That first race was won by William Grover-Williams (a.k.a. "Williams") driving a Bugatti. The event was part of the pre-Second World War European Championship and was included in the first Formula One World Championship in 1950. The race is held on a narrow course laid out in the streets of Monaco, whose many elevation changes and tight corners make it one of the most demanding tracks in Formula One. On the race weekend frogmen (divers) are employed to rescue any drivers who happen to crash into the harbour.