On this day in 1964, Brazilian president João “Jango” Goulart was overthrown by the military, and a military dictatorship was installed in his place.
Goulart’s presidency was too left for some, which is why he was overthrown. He had been the latest in a long road towards democracy in Brazil, and the military coup ended up derailing that path for twenty years.
You can read more about Brazil’s military dictatorship and Goulart at the link.