In the Herbst Theatre and adjoining War Memorial Veterans Building, representatives of 50 countries signed the founding charter of the United Nations, capping a two-month conference held amid the rubble of a war not yet over in the Pacific. Poland, absent from the ceremony, later became the 51st signatory. The charter entered into force that October.
The delegates who gathered in San Francisco in the spring of 1945 worked under a strange duality: Germany had just surrendered, but the war against Japan raged on, and news of Hiroshima was still six weeks away. They were designing an institution to prevent future wars while one was still being fought.
Each delegation signed five copies of the charter, in English, French, Chinese, Russian, and Spanish, using a fountain pen dipped repeatedly to allow signatories to keep the pens as souvenirs. The signing took hours because of the sheer number of delegations and the alphabetical ordering that placed Argentina first and Yugoslavia last, with the United States deliberately signing next-to-last, ahead of only the host country's own late alphabetical slot arrangement.
President Harry Truman addressed the closing plenary session, warning that the charter was 'not a perfect document' but a place to build from. Within five years the fledgling organization would be tested by the Korean War, and within decades its Security Council veto structure would freeze it during Cold War standoffs. Still, the UN Charter's signing remains one of the 20th century's most consequential documents, establishing the legal architecture for international law, peacekeeping, and human rights frameworks used ever since.