The international city network Mayors for Peace, which campaigns for a nuclear-free and peaceful world, has called on its members to take part in the International Day of Peace and fly the flag on September 21. As the International Day of Peace fell on a Sunday this year, the flags were hoisted by the city of Wolfsburg at the beginning of the week.

The International Day of Peace, also known as World Peace Day, was proclaimed by the United Nations on November 30, 1981 and aims to achieve a peaceful, non-violent world and a global ceasefire. Since 2002, it has been celebrated annually on September 21. In Germany, September 1 is already celebrated as World Peace Day because the Anti-War Day, which commemorates the beginning of the Second World War, is celebrated on the same date.