united-nations:

29 April is Day of Remembrance for all Victims of Chemical Warfare. It’s the date in 1997 on which the Chemical Weapons Convention entered into force. 

This Day provides an opportunity to pay tribute to the victims of chemical warfare, as well as to reaffirm the commitment of Organisation for the Prohibition of Chemical Weapons (OPCW) to the elimination of the threat of chemical weapons, thereby promoting the goals of peace, security, and multilateralism.

(via united-nations-deactivated20190)