Those are INDEED some mammoth sunflowers !!
I got several diff. types of seeds this spring, mixed them all together (some only get 3ft, some up to 10 it says on pkg) and planted a 20 ft. row along the side of our veggie garden. I also have dahlia and zinnia growing in that same area. Would we ever impress the neighbors when they could see the flowers above the 6ft privacy fence!!! LOL We basically planted them not only for the beauty, but for the birds as well. HOPEFULLY we'll have some left to actually get full heads on them before birdy friends attack them. LOL