“Hoping to beat the Americans to the moon before 1970, Soviet rocket engineer Sergey Korolyov worked in secret to plan the mighty N-1, an equal to the American Saturn V booster. In 1966 however, the sudden death of Korolyov threw Soviet plans into disarray. After four N-1s were lost in catastrophic accidents, the Soviets destroyed the remaining hardware and denied the very existence of the program. The N-1 remained a state secret until being made public in 1990.” Taken from the infographic below: Source Space.com: All about our solar system, outer space and exploration