On 13 June 1938 German police began a week of operations against Roma and Sinti people in Germany.
Every June, we celebrate Gypsy, Roma and Traveller History Month (GRTHM) in the UK.
On 26 May 2011, General Ratko Mladić was captured and arrested after avoiding arrest for 16 years.
In 1984, the Cambodian government declared 20 May a National Day of Remembrance, to commemorate the victims of the genocide in Cambodia that took place between 1975 and 1979.
Each year on 17 May, the UK and countries across the world mark the International Day Against Homophobia, Biphobia and Transphobia (IDAHOBIT).
16 May marks the end of the Warsaw Ghetto Uprising, which started on 19 April 1943. Approximately 750 of the ghetto inhabitants fought the Nazi regime to resist being rounded up and taken to death camps and concentration camps.
On 6 May 1933, the Institute of Sexology, an academic foundation devoted to sexological research and the advocacy of homosexual rights, was broken into and occupied by Nazi-supporting youth. Several days later the entire contents of the library were removed and burned.
On 5 May 1945, Mauthausen Concentration Camp was liberated by the US Army.
On 2 May 1933, just three months after Adolf Hitler’s appointment as Chancellor of Germany, the SA and police occupied the offices of German Trade Unions, seizing control of them.
On 30 April 1994, the United Nations (UN) debated the unfolding Genocide in Rwanda, and whether or not the International Community should intervene to prevent the killings.