While there are a lot of reports (and recently faked photographs) all are at best dubious and there is no physical evidence of a race of humans outside the usual range. Individuals may be unusually tall, some peoples are taller than others but that is all that can be confirmed. A lot of older reports of giant bones are likely the bones of large animals, and not human at all.
So, a few individuals that reach seven feet tall - quite likely. But certainly nobody near twelve feet.