The Soviet Union’s second attempt to launch its moon rocket, the huge N1, ends disastrously. Again carrying an unmanned Zond spacecraft, the N1 barely clears the tower before stalling. Still full of highly flammable fuel, the N1 drops back to the ground, resulting in one of the most powerful man-made, non-nuclear explosions in history, completely wiping its launch tower and adjacent buildings off the map. (The Zond probe is lifted clear of the explosion by its escape rockets.) American spy satellites spot the damage to the nearby landscape from the explosion, tipping off the rest of the world to the N1 rocket program.