4 years ago I had made the retaining wall but my wife and I couldn't agree on how the top was to be done. She wanted the planters to be continuous, and I told her there would be not support for the backing blocks. So I out waited her until she gave up and said, "Go ahead be bull headed and just do it!" So here it is for you to see. I'm 71 years old and so I couldn't use my cement mixer as I couldn't lift the bags of cement that high. I had to mix each batch in the tub shown in the second picture. It took 14 bags of Quick-krete per form. I also put two shovels of pea gravel with each bag along with 3/8 inch re-rod each form distance is 8 foot with a 6 foot planter box in the center. its 156 feet total distance. I attached the back blocks with construction cement. It will last until I won't be here. I hope you enjoy the pictures. My wife finally came around and agrees she love it now with the flowers.