The Queen has often shown courage, ever since she joined the military at 18. During a trip to Ghana in 1961, she was warned that it was dangerous to be near the President Kwame Nkrumah because people wanted to kill him. But she refused to stay away. The Prime Minister of the United Kingdom, Harold Macmillan, wrote that the Queen got very impatient with people if they tried to treat her like "a film star".