The Journées Arithmétiques (JA) have a glorious history. Their first edition was held in 1960 in Grenoble and starting in the 1980’s the location alternates between France and another country in Europe. The JA have toured the United Kingdom, Switzerland, Spain, Italy, Austria, Lithuania, Hungary, Turkey, and are now coming to Luxembourg. Some major results in number theory were first presented at JA, such as the proofs of the irrationality of zeta of 3 by Apéry, of the Iwasawa Main Conjecture by Coates and Wiles, and of the Mordell Conjecture by Faltings.
Nowadays, the event is probably the largest number theory gathering in the world, attracting both junior and senior mathematicians (the last edition hosted more than 300 participants from 42 countries). The last two editions were held in Nancy and Istanbul. JA25 is the 33rd edition, in the year (20+25)².