(CNN)About halfway up the cobblestone stairwell, the screeching starts.
Loose stones tumble from the tops of the walls far up on the hilltop.
All around me, tree limbs shake.
It's just after dawn, and I'm alone, climbing the trail to the 15th-century royal compound on the hilltop at Great Zimbabwe in southern Africa.
Alone, except for the baboons.
Like all the stone structures here, the stairwell is open to the sky, but the incline is so steep and the curves so sharp that I can't see more than 10 feet in front of me.
Sure enough, around the next bend a baboon is waiting for me on one of the dozens of terraces that skirt the hillside.
We watch each other for a few moments until I'm certain he's not interested in me, and then I keep walking.
Baboons freak me out, but these moments are part of what makes Great Zimbabwe such an incredible place to visit.