Angels Landing, Zion
As trail gets steeper there is less green. Only strongest trees survive harsh conditions of the rocks.
The most challenging and breathtaking part of the journey is the last half mile. It has steep drop-offs from both sides and sometimes the trail itself is as narrow as couple feet.
I can't recommend taking this trail if you have fear of heights. I saw two terrified tourists up there who seemed too afraid to walk even before the actually dangerous places.