The Charter of the United Nations was signed on June 26, 1945, in San Francisco, California, by 50 countries. It entered into force on October 24, 1945.

The Treaty of Versailles was signed on June 28, 1919, between the Allied Powers and Germany. It ended World War I, established the League of Nations, and demilitarized Germany.

The Treaty of Rome was signed on March 25, 1957, by six countries: Belgium, France, Germany, Italy, Luxembourg, and the Netherlands. It established the European Economic Community (EEC), which later became the European Union (EU).

The Geneva Convention is a series of treaties that protect civilians and regulate the conduct of warfare. The first Geneva Convention was signed in 1864, and the most recent was signed in 1949.

The Marrakesh Agreement was signed on April 15, 1994, in Marrakesh, Morocco. It established the World Trade Organization (WTO), which is responsible for regulating international trade.

The Kyoto Protocol was signed on December 11, 1997, in Kyoto, Japan. It is an international treaty that aims to reduce greenhouse gas emissions in order to combat climate change.

The Rome Statute was signed on July 17, 1998, in Rome, Italy. It established the International Criminal Court (ICC), which is a permanent international court that investigates and prosecutes individuals for genocide, crimes against humanity, war crimes, and the crime of aggression.

The Paris Agreement was signed on December 12, 2015, in Paris, France. It is an international treaty that aims to limit global warming to well below 2 degrees Celsius, and to pursue efforts to limit it to 1.5 degrees Celsius.

The Bangkok Declaration was signed on August 8, 1967, in Bangkok, Thailand. It established the Association of Southeast Asian Nations (ASEAN).

The Treaty on the Non-Proliferation of Nuclear Weapons (NPT) was signed on July 1, 1968, in London, Moscow, and Washington, D.C. It aims to prevent the spread of nuclear weapons, promote nuclear disarmament, and establish a system of international nuclear safeguards.

The Helsinki Final Act was signed on August 1, 1975, in Helsinki, Finland. It established the Organization for Security and Cooperation in Europe (OSCE).

The Montreal Protocol on Substances that Deplete the Ozone Layer was signed on September 16, 1987, in Montreal, Canada. It aims to protect the ozone layer by phasing out the production and consumption of ozone-depleting substances.

The Constitution of the World Health Organization (WHO) was signed on July 22, 1946, in New York City. It established the WHO as a specialized agency of the United Nations.

The Convention on Biological Diversity (CBD) was signed on June 5, 1992, in Rio de Janeiro, Brazil. It aims to conserve biological diversity, promote sustainable use of biological resources, and ensure the fair and equitable sharing of benefits from the use of genetic resources.

The United Nations Framework Convention on Climate Change (UNFCCC) was signed on May 9, 1992, in New York City. It aims to stabilize greenhouse gas concentrations in the atmosphere at a level that would prevent dangerous anthropogenic interference with the climate system.