My First Rattler
This timber rattlesnake was both the first rattler and venomous snake I ever saw. Fortunately she was sitting up on a bleached-out dead tree that I had walked by several times before, so even from a distance I immediately noticed something had changed. I slowly approached but kept my distance and could clearly see the classic viper headshape, so I knew she was dangerous even though her rattle was hidden (and silent).
Undisturbed
I carefully circled around to her front, moving slowly and keeping a good distance to keep both of us in our comfort zones. It must have worked as she never stirred apart from occasionally flicking her tongue. This picture was taken from the side and you can see her head poking out from her coiled body.