I've been reflecting on the myths of slenderman and ancient races of giant humans.
People have claimed to see slenderman, even though the guy who originally posted a picture of slenderman that he later said he had faked.
Even though some say the idea of an ancient race giant humans is all myth, you can still see extremely tall humans in different races. These people are often plagued with health problems.
I'd like to speculate that if there was an ancient race of such huge people, then perhaps they died out for the most part because of genetic, environmental and/or disease-related problems. When they originated, there may have been geophysical conditions that allowed them to prosper. When these conditions started to go away, they could have sickened and mostly died off, while smaller races of people could do just fine.
Here's an interesting link about giants: