International Chernobyl Disaster Remembrance Day

Day of Freedom from Fascism and Memorial Day of the Evangelist Mark in Italy on April 25;

International Workers' Memorial Day on April 28;

Shōwa Day in Japan on April 29 (昭和の日 is celebrated in Japan to commemorate the birth date of Emperor Showa or Hirohito, the emperor of pre and post-World war II);

Cassinga Day in Namibia on May 4;

Dave Brubeck Day on May 4 (David Warren Brubeck (December 6, 1920 – December 5, 2012) was an American jazz pianist and composer, considered to be one of the foremost exponents of cool jazz. In the United States, May 4 is informally observed as "Dave Brubeck Day". In the format most commonly used in the U.S., May 4 is written "5/4," recalling the time signature of "Take Five", Brubeck's best known recording);

Remembrance Day for Martyrs and Disabled in Afghanistan on May 4;

UN remembrance and reconciliation DAY on May 9 (8–9 May);