UFO Sighting in Grass Valley, California on May 31st 1968 – Cigar shaped object that slowly flew over

I was 6-8 years old. My sister and I were out walking through Manzanita groves looking for snakes. I spotted a white object that was slowly flying over. I pointed it out to my sister and we watched. It was only a few hundred feet up. I was scarred but it was if I couldn't move. It was white almost like a rocket ship that the US had been sending into space. It had markings on it but not in anything I have ever seen. It never stopped, just flew over slowly making no sound. After it disappeared we ran back up to the house and tried to explain it to our Grandmother. She just discounted us and thought we had made up the story. My sister and I never spoke about this again.