On July 3, 1969, the biggest explosion in the history of rocketry occurred when the Soviet N-1 rocket exploded and subsequently destroyed its launchpad. After four unsuccessful launch tries of the Soviet counterpart to the NASA Saturn V rocket the Russian Moon program was cancelled in May 1974.
S. Doerfel, R. Jäschke, A. Hotho, and G. Stumme. Proceedings of the 4th ACM RecSys workshop on Recommender systems and the social web, page 9--16. New York, NY, USA, ACM, (2012)