Here is a picture taken yesterday of my corn with tassels & ears. The person who gave me the seeds said it shouldn't form silk on the ears, but I have some that does. The tallest is around 17 feet tall. If you look above the plume of the tallest red amaranth you can see a large ear. Some of the ears look nearly 2 feet long, but I haven't measured them yet.
My marrows ended up being terrible this year. The heat wave did them in. However, my neighbor up in New York, Jonny 5, tried gardening for his first time this year and he had a 15 pound marrow from seed I gave him. He also had a Bott's Strain sunflower that grew close to 12 feet tall. Not bad for his first try at gardening.