Between Williams and Flagstaff, along US highway 40, sits a neat grotto tucked away into the National Forest along an unassuming stretch of road. The area is a peaceful stretch, but finding the trail head to this grotto isn’t far from the highway. Finding the parking lot is a simple as typing “Keyhole Sink” into your favorite GPS, occasionally with adding “Arizona” to the search, depending on your settings. The parking lot is a little up the road from where the “pin drops” on the GPS, though you can find the parking lot on the south side of the road, and it is a dirt lot, so be careful during or after heavy rain.
The trail head is across the street from the parking lot, and is blocked by a gate with a chain, make sure to close the gate behind you. The trail itself if a comfortable meander through the woods for one mile, however my GPS said it was only 2/5 of a mile (one way). Most of the hike has ample tree cover, providing shade, but there are enough gaps that if the UV index is high enough you could heat up, so be sure to have sunscreen handy. The very end of the trail get a tad rocky, but little to none of it is loose, and its easy to avoid the rocks and not have to worry about foot placement.
The grotto itself has no cover from the sun, but can have high grass and a sizable pool of water (depending on rainfall), there is also the rare chance of a waterfall to be present if rain falls in the right place, and you are there at the right time. Petroglyphs are present exclusively on the left hand side of the grotto, from the perspective of the entrance, i.e. the west side. A couple stray petroglyphs can be found, but the two main panels are in the back left, keep your head on a swivel and inspect the rocks around you.