46 BC: Julius Caesar defeats Caecilius Metellus Scipio and Marcus Porcius Cato (Cato the Younger) in the battle of Thapsus.

1453: Turkish forces under Sultan Mehmed II begin the siege of the Byzantine Empire capitol of Constantinople (now İstanbul), which falls May 29

1652: Cape Colony, the first European settlement in South Africa, established by Dutch East India Company under Jan van Riebeeck

1917: The United States declares war on Germany and enters World War I on the side of the Allies

1994: Plane carrying Rwandan President Juvénal Habyarimana and Burundian President Cyprien Ntaryamira is shot down by surface-to-air missiles, abruptly ending peace negotiations and sparking the Rwandan Genocide. Those responsible have never been identified.

Source:Onthisday.com