46 BC: Battle of Thapsus: Julius Caesar defeats Caecilius Metellus Scipio and Marcus Porcius Cato (Cato the Younger) near Thapsus in modern-day Tunisia

1453: Turkish forces under Sultan Mehmed II begin the siege of the Byzantine Empire’s capital, Constantinople (now Istanbul), which falls on May 29

1652: Cape Colony, the first European settlement in South Africa, is established by the 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
Skulls of genocide victims at the Nyamata Memorial Site in RwandaRwandan Genocide

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