Short answers, pulled from the story.
The Constitution of UNESCO came into force on the 4th of November 1946 after receiving its twentieth ratification. The organization officially began operations following a conference in London from the 1st to the 16th of November 1945 where thirty-seven countries signed the founding document.
Julian Huxley served as the first Director-General of UNESCO from 1946 to 1948. Rab Butler developed much of the idea behind the organization while serving as Minister of Education for the United Kingdom during the planning phase.
The International Campaign to Save the Monuments of Nubia launched in 1960 moved twenty-two monuments including the Great Temple of Abu Simbel. The World Heritage List included its first sites such as Kraków in Poland and the Historic Center of Quito in Ecuador on the 18th of September 1978.
The UN General Assembly declared the 3rd of May as World Press Freedom Day after the organization endorsed the Windhoek Declaration in 1993. Since 1997 the organization awards the UNESCO / Guillermo Cano World Press Freedom Prize every year on that date.
Israel left UNESCO on the 31st of December 2018 after sixty-nine years of membership citing continuous anti-Israel bias. Nicaragua announced a withdrawal decision on the 4th of May 2025 effective the 31st of December 2026 while the United States stated intent to rejoin in 2023 before announcing another withdrawal in 2025.