Why is hard to imagine that Giants existed?! We have had giants animals in all area of the world. Giant penguins in Antartica for example. Its life adaptation. I think we must look for giant bones in areas that were once hard to found food. Look at elaphant. His stomach is big because it was hard to him to find good nutrition food so to survive he must eat a lot of low quality food that his stomach could choose best nutrition from it. So to become Giant we must first asumme that Darwin theory is right and give homo spieces enough time and area with low quality food and you will get Giants.
I'll tell you something.
Egyptians, and Mediterranean people (ancient Italians, Greek, Egyptians) in general were always rather small, in ancient times and many still are now.
And then there were the Nordics: Scandinavians, Danes, Frisians, and so on.
The people living at the coasts of the Med thought of them as giants.
They were on avarage 6 feet tall, and some were a bit larger.
What would you have thought. of them, living there back then?