Formed in Brussels, Belgium, on 28 July 1919, the International Union of Geodesy and Geophysics (IUGG) celebrates its 100th anniversary in 2019. The centennial year marks an important milestone for IUGG. Since its inception as a union of international scientific associations, IUGG has evolved into a prominent scientific organization promoting Earth and space sciences worldwide in the complex political, economic and scientific landscapes of the 20th and the beginning of the 21st centuries. IUGG’s mission is to advance, strengthen and promote Earth and space sciences for the benefit of humanity through international research cooperation and education, and to communicate the knowledge to governments and policymakers. For the decades ahead, IUGG envisions a future Earth that is environmentally sustainable and where societies are resilient against natural hazards. We celebrate the IUGG centennial not only to remind geoscientists how important international scientific cooperation is and how IUGG science and science diplomacy have developed over the last century, but also to think collectively about future scientific developments, international scientific initiatives, and finding solutions to the urgent problems of our society, especially to those related to the 2030 UN Agenda for Sustainable Development. We are looking at the past in order to develop a new future for Earth and space sciences and to promote science for the benefit of all.

To celebrate the Centennial of the Union, IUGG established a Task Force to develop a program for celebrations around the world for 2018-2019. In 2018, several conferences/symposia and a summer school for early career scientists were held in China, Japan, Mexico, Turkey, and the USA. The program for this year includes:
-    27th IUGG General Assembly, Montreal, Canada, 8-18 July 2019;
-    Celebration of the IUGG Centennial at UNESCO, Paris, France, 29 July 2019;
-    Several meetings in Europe, South America, and the Middle East;
-    A special volume on “The International Union of Geodesy and Geophysics: From Different Spheres to a Common Globe” will be published as a part of the peer-reviewed journal History of Geo- and Space Sciences.

As a part of this program, a website dedicated to the IUGG Centennial has been developed and is now open to the public. Please visit http://100.iugg.org/ to learn more about the history of IUGG. We hope all visitors to the website, especially IUGG scientists from all nations and geoscientific disciplines, will enjoy this wonderful 100-year journey through space and time and appreciate the work of several generations of Earth and space scientists, who voluntarily contributed their time and efforts to the development of international cooperation in geosciences.

Michael G. Sideris, IUGG President
Alik Ismail-Zadeh, IUGG Secretary-General