Answer:
Ethel and Julius Rosenberg.
Step-by-step explanation:
Ethel and Julius Rosenburg were two American citizens who were convicted of giving atomic secrets to the Soviet Union. This happened at a time when the United States was the only country that had nuclear technology. The couple was convicted of espionage and executed in 1953 in New York. These were the only two American citizens to be executed for espionage during the Cold War.