The Moncada Barracks. On July 26, 1953, Fidel Castro and 100 rebels launched an assault on the Moncada barracks, the headquarters of Batista military in the south, and the second most important military garrison in the country.
The attack failed, and Fidel escaped to the nearby Sierra Maestra mountains. He was later captured and put on trial, where he defended himself and delivered his "History will absolve me" speech. Over one-third of the rebels were immediately captured; they were tortured and killed. Fidel returned on November 30, 1956 which led to the "triumph of the Revolution" on January 1, 1959.
The Barracks are now a school and the Museum of the Revolution.