I was hiking with my brother and two small sons on a marked trail that crossed an exposed mountainside. The slope wasn't that steep but there was no vegetation. We noticed a herd of bighorn sheep running above us maybe 150 yards and quietly stopped to watch.

They looked like a flock of birds changing direction abruptly every few seconds. Their speed - maybe 20 mph - never changed. Finally, they turned straight down the mountain directly at us. There was nowhere for us to hide. My brother picked up my oldest and I picked up my youngest. The rams charged at us and right as they got to us, the herd split in two and passed us on either side close enough to touch. The adrenaline was going pretty good on that one!