Why is so much of the Grand Canyon off limits?

Why is so much of the Grand Canyon off limits? 

Why did famous explorers like John Wesley Powell describe finding Egyptian hieroglyphics and other artifacts in the Grand Canyon? 

It’s the same reason why you find pyramids all across America as well as many other ancient megalithic structures. In this realms advanced past we were far more connected and capable than any history book will have you believe. There has been many resets erasing and burying so much of our past. I don’t believe the parasites caused it but has passed on knowledge of these events. These select families have been hoarding technology and resources to maintain continued control over the masses. Those who control history, controls the world.