Badlands NP is amazing.  I ditched the main camp during an evening and took a little hike out. and up a gully.  a bull saw me and chased me into a thicket of bushes.  it trotted at me from a far distance away but didn't stop coming, so I had to get out of the way!

I eventually got back to the camp area.  I woke up earlier than most others the next day and a bull and a heifer walked right through camp.  literally right next to nylon tents.  everything was peaceful that morning but some humans got spooked

really great experience. I loved seeing wild bison