The first attempts to internationalize the ABC television network date back to the 1950s, after Leonard Goldenson, following the United Paramount Theatres model, tried to use on ABC the same strategies he had made in expanding UPT's theater operation to the international market. Leonard Goldenson said that ABC's first international activity was broadcasting the coronation of Queen Elizabeth II in June 1953; CBS and NBC were unable to cover the coronation live due to respective issues with technical problems and flight delays. NBC's plane landed in Latin America[where?], leading ABC to learn of subsidiaries in that region. Goldenson tried international investing, having ABC invest in the Latin American market, acquiring a 51% interest in a network covering Central America. Goldenson also cited interest in Japan in the early 1950s, acquiring a 5% stake in two new domestic networks, the Mainichi Broadcasting System in 1951 and Nihon Educational Television in 1957. Goldenson also invested in broadcasting properties in Beirut in the mid-1960s.