Question

What incident caused Castro and Cuba to be closely allied with Russia

Answer 1

Answer:

it is the Bay of Pigs fiasco

Answer 2

it was the Bay of Pigs Fiasco.  It was an invasion of Cuban exiles whose goal is to overthrow the government of Fidel Castro.  It was launched in Guatemala by CIA-trained counter-revolutionary forces known as Brigade 2506.  Though they were supported by American bombers who bombarded the Cuban airfields and managed to overwhelm a small militia, they were crushed by a Cuban counter-offensive by Jose Ramon Fernandez. Later, Castro himself led the attack and the invaders surrendered and were imprisoned on April 20, 1961.