Largest postcard number

The largest postcard number is 6,666 and was achieved by the Swiss Agency for Development and Cooperation SDC / Section Water (Switzerland) in Basel, Switzerland, on 12 April 2024

The SDC is Switzerland's international cooperation agency within the Federal Department of Foreign Affairs. This attempt was organised to promote one of their projects, The 1 Million Youth Actions Challenge, featuring a postcard number that symbolically represented the number 1,000,000. The 1MYAC project encourages youth worldwide to take concrete actions for a more sustainable future. The objective is to reach 1,000,000 youth actions, encompassing initiatives such as beach or river cleanups, installing rainwater recycling devices, etc...

The postcard installation was prominently showcased at Basel Messe, the city's conference venue, for the International Cooperation Forum on peace. Every postcard incorporated in the installation featured quotes about water and peace from young people across the globe. These quotes were presented in both the local language and translated into English.