Final answer:
During the Cuban Missile Crisis, the USSR promised to remove missiles from Cuba in exchange for the United States not invading the island.
Step-by-step explanation:
The USSR promised to Cuba during the Cuban Missile Crisis was to remove all missiles from Cuba in exchange for the United States agreeing not to invade the island. As part of the agreement, President Kennedy also secretly removed missiles from Turkey. This resolution helped avert a potential nuclear war between the United States, the Soviet Union, and Cuba.