It is no secret that Mathematica has a big user community that is alive and kicking. It may, however, surprise you that the global user community has successfully organized 10 international Mathematica conferences around the world. It all began 20 years ago in the city of Rotterdam, the Netherlands, about two meters below sea level, where Wolfram Research had organized the Mathematica Days. The Mathematica Days were a small sibling of the larger annual Mathematica Conference, which in those days had its venue 8,800 km farther west in the Bay Area. Among the participants in Rotterdam were Peter Mitic (The Open University, UK), Gautam Dasgupta (Columbia University, New York), Pertti Näykki (Finland), Klaus Sutner (Carnegie Mellon University, Pittsburgh), Robert Kragler (Fachhochschule Ravensburg, Weingarten, Germany), and Veikko Keränen (Rovaniemi Institute of Technology, Finland). Most of them met for the first time and came from different walks of life, but they all shared the same enthusiasm for algorithmic mathematics. The lack of an academic conference targeting innovative work in, with, and about Mathematica triggered Peter Mitic to propose the idea of a symposium. His new friends very much supported the endeavor, and in 1994 Stephen Wolfram became the godfather of the new event by suggesting the name "International Mathematica Symposium" (IMS). In July 1995, the first IMS in Southampton, England, began an uninterrupted streak of biannual, and for some years even annual, symposia. In contrast to the Wolfram Developer/Technology/User Conferences with their venue in Champaign, Illinois, the IMSs have roamed the world. The second IMS took place in Rovaniemi near the polar circle in northern Finland, followed by Hagenberg near Linz in Austria, Tokyo in Japan, London—the one in England, Banff in Canada, Perth in western Australia, Avignon in the south of France, Maastricht in the Netherlands, and Beijing in China.