I remember standing on a small pier in Cam Ranh. Looking down through this crystal clear water, down to the bottom to this beautiful white sand that was rippled, and wondering how far down it was. I'd never seen anything this pure and clean before, even swimming pools had chlorine that gave it a slight 'haze'. I had a coin, 10 piastre?, that I pulled from my pocket. I flipped it into the air, watched it hit the water, then I watched as it began to slowly tumble, catching the sunlight and 'twinkling' back at me as it slowly spun it's way to the bottom. When it hit the bottom, I could see a slight 'puff' of sand jump from the landing spot. It was incredible. I guessed by the length of time it took for the coin to reach the bottom, it must have been 10 feet deep. 50 years ago. I still remember that. At one time, Mother Earth must have been so beautiful, so clean, so pure.