As early as 1951, the High Commissioner for Refugees (UNHCR) opened a liaison office in the then federal capital Bonn, and in 1953 an office of the International Labor Organization (ILO) was established.

In 1979, the Convention on the Conservation of Migratory Species of Wild Animals was adopted at Godesburg Castle. The Bonn Convention opened its doors in Bonn in 1984 as the first independent UN institution and is still based here today.

The Bonn-Berlin resolution of June 20, 1991 set a new goal for Bonn "to take over and establish new functions and institutions of national and international importance". With the Berlin/Bonn Act and a compensation agreement, Bonn was able to create the appropriate infrastructure for this role, in particular the spatial conditions for the future work of multilateral institutions.

The United Nations was the first new organization to relocate its volunteer programme from Geneva to Bonn. At the same time, the German government was awarded the contract for the new climate secretariat at the 1995 climate summit in Berlin. The first building to be handed over to the United Nations was a place of historical significance: "Haus Carstanjen", idyllically situated on the Rhine, was the place where the Marshall Plan was agreed and signed after the Second World War.

In 1998, the Bonn Convention was joined by two new regional agreements: the Secretariat of the Agreement on the Conservation of Small Cetaceans of the Baltic and North Seas (ASCOBANS) and the Secretariat of the Agreement on the Conservation of European Bat Populations (EUROBATS).

The highlight of the first decade of settlement was certainly the arrival of the Secretariat of the Convention to Combat Desertification (UNCCD). At this point, Bonn could already point to a network of institutions that, in the wake of the Rio Conference in 1992, dealt with issues of sustainability and thus the future viability of our planet.

And year after year, new organizations were added, mostly small but growing steadily.

Another milestone in the development of the UN location in Bonn was July 11, 2006: the German government made the former high-rise parliament building, also known as "Langer Eugen", available to the United Nations. Kofi Annan and Chancellor Angela Merkel officially opened the new headquarters. "The great hospitality we have received here has made Bonn one of the most attractive and rewarding places to work for the United Nations," said the UN chief at the ceremony. And the Federal Chancellor added: "We want - and this is an express wish of the entire Federal Government - to further expand the UN location here in Bonn, with a focus on the environment and development."

The UN Tower is the focal point of the UN Campus. The headquarters of the UNFCCC are located in the immediate vicinity in the Old Parliament Building. The building has been refurbished as an ecological model building. The waterworks and pump house were also added to the UN Campus to provide the facilities with space for smaller meetings. Carstanjen House is still in use and another building is already under construction.

The history of the UN Bonn is a success story. The city of Bonn celebrated its 20th anniversary as the German city of the United Nations with a diverse program of public and specialist events from April to November 2016. The people of Bonn joined in the celebrations. In June 2016, around 10,000 visitors attended the citizens' festival at Villa Hammerschmidt and the Federal Ministry for Economic Cooperation and Development (BMZ). There will also be an anniversary program for the 25th anniversary in 2021. Further information can be found here.

The UN city has long since become a recognized international location: Over 150 non-governmental organizations work from here and are also mostly active in the field of sustainability. A special field of gravity for sustainability developed in particular with the adoption of the 2030 Agenda in September 2015. Bonn is now not only the headquarters of the Global Action Campaign for the 17 Sustainable Development Goals (SDGs), but also a knowledge center for sustainable development of the United Nations Staff College. Institutions from science and research, as well as global players from the business world, complete the picture.

The UN staff in Bonn agree with their former boss Kofi Annan: "Bonn is so romantic, so familiar and so safe" is a recurring theme.

A city that is the seat of the United Nations needs a suitable conference infrastructure, even for large conferences of signatory states. The Bellevue Agreement, signed on February 27, 2002, marked the beginning of the expansion of the World Conference Center Bonn. In the presence of UN Secretary-General Kofi Annan and Federal President Johannes Rau, the Federal Government, the State of North Rhine-Westphalia and the City of Bonn sign the agreement on the establishment of international institutions in Bonn and on the conference center.

United Nations meetings and conferences have become an important feature of Bonn's location. Peace, voluntary commitment, species protection, early warning of disasters, combating land degradation and climate protection are just some of the topics that the United Nations has brought to Bonn. The Climate Change Secretariat is by far the largest conference organizer - three Conferences of the Parties have been held in Bonn, most recently with more than 22,000 participants in autumn 2017.