The Pinnacles are an outcropping of tectonic plates. The result is an area of immense rocks that spring out of the horizon. In this national park, John and I hiked along the base (where the face of the rock extends, quite literally, vertically up from the earth.
On our way back, we travelled under the rock formation. Yes, under the rock formation. There are narrow passage ways that exist - at ground level - under the edge of the huge rock formations. Flashlights are required in some places, because no light from the outside reaches certain caverns. The walk is not long, but some climbing was involved. Mostly the walk was a pleasant reminder of how small we are as compared to the boulders wedged above our heads.