The second decade of The Queen's reign saw the introduction of further innovations to make the work of the monarchy accessible to an even wider range of people. During their visit to Australia and New Zealand in 1970, for example, The Queen and The Duke of Edinburgh initiated a new practice - the 'walkabout' - to allow them to meet as many people as possible. Increased access to the lives of members of the Royal Family by the media was allowed. In 1969 the first television film about the family life of the Royal Family was shown. 'Royal Family' was watched by 23 million viewers and included footage of the off-duty activities of The Queen and her family. Another innovation was the opening in 1962 of a new gallery at Buckingham Palace to display items from the Royal Collection. The brainchild of The Duke of Edinburgh, the new Queen's Gallery occupied the space of the Palace's bomb-damaged private chapel. It was the first time that parts of the Palace had been opened to the general public, and proved very popular. In politics, the issue of The Queen's Royal prerogative in politics arose again in 1963, as it had done in 1957. Following the retirement of Harold Macmillan, The Queen acted on the advice of Macmillan in appointing Lord Home Prime Minister and leader of the Conservative party. The choice caused some controversy, and in 1965 the Conservatives instituted an electoral procedure by which to decide the Party's leadership in the future. The Queen has played no role in the election of Conservative Party leaders subsequently. The Queen made several historic overseas visits, including the first visit by a monarch to West Germany since the war. In the divided city of West Berlin, The Queen surveyed the Berlin Wall. Other members of the Royal Family attended the independence ceremonies of countries formerly in the British Empire, giving rise to the Commonwealth in its present form as a network of countries sharing friendship across the globe. The Queen and The Duke of Edinburgh had a new addition to their family with a fourth child, Prince Edward, in 1964. Prince Charles and Princess Anne began to undertake their first Royal duties in support of their parents' work. Prince Charles' role as heir to the throne was formally acknowledged when The Queen invested him as Prince of Wales in a ceremony at Caernafon in 1969. The ceremony was watched on television by 200 million people worldwide.