September 21 will be the annual International Day of Peace. Developed by the U. N., many, many peace groups and related organizations, religious groups, and individuals will have different activities to commemorate the day and continue showing dedication to peace. The theme this year is "The Right of Peoples to Peace."
Here is a good background site: UN PeaceDay. There will be many events all over the world - gatherings, concerts, video and social media happenings. One worldwide event is to be a coordinated prayer /meditation for peace at noon in each time zone. And if you happen to be looking for peace prayers, I shared a link to some Episcopalian ones in this post
Another site with great information and resources is World Beyond War . They have a calendar of peace-related dates you can view on site or download located here.
So prepare yourself to commemorate the International Day of Peace. And again, don't forget the music!