National Peacekeepers' Day is celebrated on August 09, 2017. National Peacekeepers' Day is an official remembrance day for Canadian veterans of military peacekeeping activities. It is officially marked on 9 August of each year and observed on the closest Sunday.
The date was chosen to commemorate 9 August 1974, when nine Canadian peacekeepers serving on UNEF II were killed when their aircraft was shot down over Syria, the highest number of Canadian peacekeepers killed in a single incident. Legislation to make the day an official national day in Canada was passed in June 2008. (With material from: Wikipedia)