In a video message marking 100 days until the Day, Mr. Ban urged people around the world to “take this Day of ceasefire and non-violence very seriously. We need to start planning for it now.”

The International Day was established in 1981 by the General Assembly, which called for people around the world to use the Day as an opportunity to promote the resolution of conflict and to observe a cessation of hostilities during it.

Mr. Ban noted that there are places where peace has been restored, adding that “much of this has happened with the help of the United Nations.”

For example, the people of Sierra Leone and Nepal have voted in democratic elections following years of conflict, and societies are rebuilding in Burundi, Liberia and Timor-Leste.

“These experiences show us that real peace is possible, if we work collectively to make it happen,” said Mr. Ban, who urged everyone around the world to begin preparing concrete activities for the Day and beyond.

“On 21 September, let us send a real signal of our universal desire for peace,” he stated.