July 26 – Hélio Oiticica is born in Rio de Janeiro, the first child of engineer, mathematics teacher, and entomologist José Oiticica Filho (1906-1964) – who was also one of the first experimental photographers in Brazil – and Ângela Santos Oiticica (1903-1972). His brothers César and Claudio are born in 1939 and 1941, respectively.

Until 1948, Hélio and his brothers are home schooled in mathematics, science, languages, history, geography by their parents. However, their intellectual development is also strongly influenced by their grandfather José Oiticica (1882-1957), a highly reputed philologist, teacher, writer, and a renowned anarchist who published the newspaper Ação Direta [Direct Action].