The United Nations is an intergovernmental organization founded to maintain international peace and security, develop friendly relations among nations, achieve international cooperation on economic, social, cultural, and humanitarian problems, and promote respect for human rights. This status results in the organization having no army and no power to impose legislation. Instead, it should be viewed as a permanent forum and treaty-making body through which sovereign states voluntarily commit to rules and then hold each other to them with varying degrees of enforceability. The organization, which currently groups 193 states, has its political headquarters on an international territory in New York City. However, several branches are based in other capitals such as Geneva, Vienna, Nairobi, London, Paris, and others. It is worth noting that long before the United Nations, international treaties were already a central feature of diplomacy between kingdoms, we can for example refer to the treaty that followed the battle of Kadesh faught between the Egyptian Empire, led by Pharaoh Ramesses II, and the Hittite Empire, led by King Muwatalli II approximatelly in 1274 or 1275 BCE, that is currently considered the older documented treaty between two kingdoms. Closer to our era, we can consider the European ones such as the Peace of Westphalia in 1648 that ended 30 years of religious wars, again after the defeat of Napoleon in 1815, and again after the Crimean War (1853-1854) between the Russian Empire and a European-Turkish coalition led by the British and French (Paris treaty 1856). In those periods, however, there was no permanent international body to facilitate treaty-making; treaties were negotiated directly by states and reflected their own diplomatic initiatives and power relations. After the First World War, international cooperation entered a new phase with the creation of the “League of Nations” under the Treaty of Versailles in 1920, the first major attempt to establish a permanent body for peace rather than relying only on treaties negotiated case by case. While successful in settling some border disputes, this league failed at its core mission to prevent the 2nd war for a combination of reasons such as the fact that it depended on leading states, the refusal of some powerful states such as the United States to join it, the fact that decisions of the council required unanimity, and the the absence of enforcement mechanisms resulting in the fact that it did not have the authority or cohesion to compel its members to act consistently. Therefore, while officially dissolved in 1946, the organization effectively ended its activities in 1939.

A - The United Nations: Goals and Origins

This failure led the Allied leaders fighting the Axis powers to consider a new structure to fix the weaknesses of the League of Nations. This resulted in the 1942 "Declaration by the United Nations", in which Allied governments pledged to continue fighting the Axis powers together, which was the 1st time the term "United Nations” was employed. The 1944 Dumbarton Oaks Conference then drafted the basic structure, and the United Nations Charter was signed by the 51 founding member states in San Francisco on 26 June 1945 and entered into force on 24 October 1945. This charter, which is still in force, marked a significant evolution in international cooperation. It was founded on a universal basis, notably regarding the sovereign equality of all member states, while also ensuring the participation of the major powers. It featured a clearer institutional structure and a Security Council able to take binding decisions in matters of peace and security. Its mandate also extended beyond the prevention of war to include human rights, economic and social development, and international cooperation more generally.

View of the Paris Peace Conference that led to the Treaty of Versailles and the creation of the League of Nations in 1920

Definitions: Under this framework, Instruments denote the normative and legal architecture of the UN, such as treaties, declarations, and charters that establish international law and standards. Mechanisms denote the procedural and operational architecture; namely, the committees, monitoring bodies, peacekeeping operations, and review processes that implement, enforce, and bring those legal standards to life.

View of the signature of the United Nations Chart by the founding countries. The photo shows the Chinese delegation led by Mr Wei Tao-ming.

B - Instruments and Mechanisms of the United Nations

To ensure efficient operation, the United Nations Charter originally established six main organs. However, one of these, the Trusteeship Council, suspended its operations in 1994 after the independence of its last trust territory. Consequently, the current active institutional framework relies on the dynamic interplay of the five remaining core bodies described below: The General Assembly, also called "the Assembly": While not a legislature, the General Assembly functions as the central platform for multilateral dialogue, where each member state has an equal voice. It debates and makes recommendations on almost any matter within the Charter's scope, approves the UN budget, elects non- permanent Security Council members, elects the Secretary-General on the Security Council's recommendation, and emits resolutions and declarations. • The General Assembly's "Resolutions" are formal decisions or recommendations on specific issues, addressing particular actions, policies, or responses to international situations. While they are not legally binding, they carry significant political and moral weight as expressions of the collective will or opinion of the international community. • The General Assembly's "Declarations" are visionary, broader statements of principles, values, or goals that articulate fundamental norms or aspirations, such as human rights standards or development goals, thereby setting out ideals that the international community agrees to strive toward. Like resolutions, they are not legally binding, but can have a strong influence on international law and diplomacy over time. The Security Council: It is the instrument whose primary responsibility is international peace and security. Under Chapter VII of the Charter, the United Nations Security Council's resolutions can be legally binding on all member states, making it the one part of the United Nations system that resembles enforceable law. However, in practice, enforcement depends on state cooperation. This Council is composed of 15 members (5 permanent: China, France, Russia, the United Kingdom, and the United States, each holding veto power, and 10 elected by the General Assembly for two-year terms. The Economic and Social Council (ECOSOC): This council coordinates the economic, social, and related work of the United Nations and its specialized agencies, and it is the body through which those agencies formally report to the United Nations system. It issues formal resolutions and decisions that set policy positions or follow up on mandates, as well as ministerial declarations and outcome documents from high-level segments. It also publishes a wide range of substantive and administrative documents, including Secretary‑General reports, thematic and country reports from specialized agencies and functional commissions, analytical background papers, official meeting records and verbatim transcripts, agendas and summary records, as well as press releases, meeting summaries, and conference or session outcome documents. The International Court of Justice (ICJ): This instrument is the United Nations' judicial organ, which settles legal disputes between states and gives advisory opinions to the United Nations' organs and agencies. Its judgments are final and binding only on the parties to a case, while its advisory opinions are authoritative but not legally binding. The Court, seated in The Hague (Netherlands), is composed of 15 judges, elected by both the General Assembly and the Security Council to nine-year terms, with no two judges hailing from the same state. While the composition is intended to reflect major legal systems and geographic regions, judges serve in an individual and independent capacity rather than as state representatives. However, it is worth noting that the Court's contentious jurisdiction depends on the consent of the states, which is currently lacking in many of them, resulting in the Court's reach not being universal. The Secretariat: It is the United Nations' administrative organ led by the Secretary- General, which supports the General Assembly, Security Council, Economic and Social Council, and International Court of Justice by providing substantive, procedural, and administrative assistance.   It implements mandates such as peace operations and sanctions, drafts reports, organizes meetings, and handles diplomatic communications, though it does not independently make binding policy. It also produces various documents, including Secretary-General reports, analytical papers, and meeting records. In addition, it manages treaty registration through the United Nations Treaty Series.

1 - The Charter Organs

These are 15 autonomous, independently founded organizations, each focused on managing specific activities. They have their own charters, memberships, and budgets, which are linked to the United Nations through formal relationship agreements negotiated with the Economic and Social Council (ECOSOC). They are part of the United Nations system but are not subordinate departments of the Secretariat. Those most frequently cited for underwater works are: The International Maritime Organization (IMO): This organization, headquartered in London, was created in 1948 convention and entered into force in 1958. It is mandated to develop and maintain a regulatory framework for shipping safety, environmental performance, and legal matters. It works through an Assembly of member states, a Council, and technical committees that issue the following four types of documents: • “Conventions” are legally binding treaties adopted by the Assembly. They establish international standards for maritime safety, security, environmental protection, and labour conditions. They come into force in the countries that have adopted them once those countries ratify them. Therefore, their implementation is mandatory in such countries, and non-compliance can lead to legal consequences. • “Codes” are detailed technical or operational rules or practices that supplement conventions. They provide uniform implementation of conventions or address specific issues such as, ship design, cargo handling, or safety procedures. They are mandatory if referenced in a convention, and recommended if adopted as non-mandatory. • “Resolutions” are formal decisions or recommendations adopted by the Assembly or Council. They can amend conventions, adopt new codes, or provide guidance on emerging issues. Their implementation is mandatory if they amend a convention, and they are non-binding if they are recommendations. • "Guidelines" are non-binding recommendations published to assist member states, shipowners, or operators, providing relevant practices or technical advice for implementing conventions and codes. They may become mandatory if referenced in national laws (in this case, they become a national standard). The International Labour Organization (ILO): This organization, which originated from the League of Nations, is headquartered in Geneva and is governed by a tripartite structure comprising government, employer, and worker delegates, all of whom vote at its International Conference. It produces two distinct instruments: • “Conventions”, which are treaties that become binding on a state once ratified, • “Recommendations”, which are non-binding guidance and are often issued alongside a Convention to provide more detailed, aspirational context. The World Health Organization (WHO): This organization, founded in 1948, is also headquartered in Geneva. Its function is to direct and coordinate international health work. Its main binding instrument is the International Health Regulations (IHR), and it issues technical guidelines on most health matters that are persuasive but not compulsory unless a state chooses to adopt them domestically. The United Nations Educational, Scientific and Cultural Organization (UNESCO): This organization, founded in 1945, is headquartered in Paris. It works through a General Conference of member states and an Executive Board to produce binding Conventions (subject to ratification), non- binding Recommendations and Declarations, and runs standing scientific programmes such as the Intergovernmental Oceanographic Commission (IOC). While these four organizations are the most commonly cited for diving and ROV operations, the other eleven organizations that follow the same management principles should also be kept in mind, as their operations complement those mentioned above. These are: The World Meteorological Organization (WMO): This body has been created to facilitate international cooperation in establishing networks for meteorological, hydrological, and geophysical observations, as well as the exchange of weather data. It is also headquartered in Geneva, Switzerland. The United Nations Industrial Development Organization (UNIDO): This organization, headquartered in Vienna, Austria, was created to promote and accelerate inclusive and sustainable industrial development (ISID) in developing countries. The International Telecommunication Union (ITU): It is a specialized agency for information and communication technologies, working to connect the world and allocate global radio spectrum and satellite orbits. It is headquartered in Geneva, Switzerland. The Universal Postal Union (UPU): This body coordinates postal policies among member nations and ensures a truly universal network of up-to-date postal products and services. It is headquartered in Bern, Switzerland. The World Intellectual Property Organization (WIPO): WIPO promotes the protection of intellectual property (such as patents, copyrights, and trademarks) throughout the world. It is headquartered in Geneva, Switzerland. The International Civil Aviation Organization (ICAO): This organization is headquartered in Montreal, Canada, and its core mission is to codify the principles and techniques of international air navigation and to foster the safe and orderly growth of international air transport. The United Nations Tourism (formerly the World Tourism Organization, UNWTO): The reason for this organization, based in Madrid, Spain, is to promote responsible, sustainable, and universally accessible tourism as a driver of economic growth and cultural understanding. The Food and Agriculture Organization (FAO): The body's function is to lead international efforts to defeat hunger, improve nutrition, and increase agricultural productivity. It is headquartered in Rome, Italy. The International Fund for Agricultural Development (IFAD): It is an international financial institution, headquartered in Rome, Italy, dedicated to eradicating rural poverty and hunger in developing countries. The International Monetary Fund (IMF): It was created to foster global monetary cooperation, secure financial stability, facilitate international trade, and promote high employment and sustainable economic growth. It is headquartered in Washington, D.C., USA. The World Bank Group (WBG): The function of this organization, based in Washington, D.C., USA, is to provide vital financial and technical assistance to developing countries worldwide to reduce poverty and support sustainable development.

2 - The Specialized Agencies

3 - Funds and Programmes

In addition to the 15 specialized agencies described above, the broader "United Nations System" also includes various funds and programmes. These are operational entities created by the General Assembly or ECOSOC to address specific global challenges. They are not Specialized Agencies but are part of the United Nations System and report to the General Assembly or ECOSOC for oversight, coordination, and alignment with the organization’s’ priorities. They also collaborate with Specialized Agencies when their mandates overlap or complement each other. Well known examples of such entities are: UNICEF (United Nations Children’s Fund): Focuses on child welfare, education, and emergency relief. UNDP (United Nations Development Programme): Works on sustainable development, poverty reduction, and governance. WFP (World Food Programme): Addresses hunger and food security, often in collaboration with FAO (a Specialized Agency). UNHCR (United Nations High Commissioner for Refugees): Protects and assists refugees. UNFPA (United Nations Population Fund): Focuses on reproductive health and population issues.

4 - Independent International Organizations with formal or historical operational partnerships with the United nations.

These organizations are not "United Nations agencies," nor are they "United Nations-related organizations" in the strict diplomatic sense. Instead, they are multi-stakeholder pillars of the global governance ecosystem that the United Nations deliberately relies on precisely because they are independent, and this separation from the United Nations bureaucracy allows them to bridge the gap between intergovernmental policy and on-the-ground technical, scientific, or private-sector realities. Two of these organizations are regularly mentioned for diving and ROV procedures: ISO (International Organization for Standardization): This well-known private, non-governmental international organization is technically a federation of national standards bodies (though national bodies often, but not always, depend on states), reputed for the numerous standards it publishes. It is based in Geneva and is governed by a General Assembly–style structure of member delegations. Its “norms” (documents not yet adopted as standards) are applied voluntarily worldwide, as with many United Nations instruments, and its Geneva seat places it in the same institutional neighborhood as the United Nations specialized agencies with which it frequently collaborates on joint standards. It also holds consultative status with the Economic and Social Council (ECOSOC), which, alongside its links with several United Nations specialized agencies, demonstrates the close ties connecting it to the United Nations. CIOMS (Council for International Organizations of Medical Sciences): This international non-governmental organization was founded in 1949 jointly by WHO and UNESCO to coordinate the international medical sciences community. It is not a United Nations body, but it was created by two United Nations specialized agencies, remains in official relations with WHO, and issues influential, though non-binding, ethical guidelines (notably on human-subjects research) that are widely adopted into national law and industry codes of practice, including in occupational and hyperbaric medicine research.