Bob, my father-in-law, hunts deer every fall in the mountains of north-central California. A number of farmers and ranchers in the area are willing to let individuals or small groups hunt on their property—if the hunters ask permission and show respect for the land. My father-in-law is one of the most congenial men I’ve ever met. It would take a surpassingly cranky landowner to turn him down.

Last year he approached a rancher and asked him if he might drive through a certain gate and do some hunting in the evening. When shadows lengthen and the October sun slips low in the west, deer begin to venture forth from their hiding places to graze.

The rancher gave Bob a thoughtful look and said, "Yeah, you can come on the land. But you’d better let me ride with you in the truck for awhile. Want to show you some things."

Now, I can imagine most men thinking, Oh, come on! Show me some things? Why do I need a passenger? Either let me in or tell me to stay out. I know how to drive, and I know how to hunt. I’m a big boy, and I don’t need a chaperone!

Bob, however, being the man he is, cheerfully assented, and the pair drove through the gate onto the ranch. They had been skimming across a wide, seemingly featureless field when the rancher suddenly said, "You’d better start slowing down."

Why? Had he seen a deer? Bob pulled his foot off the accelerator. But why stop? As far as he could see, there were no creeks, gullies, or fences. Just a wide pasture stretching out to the dusky foothills.

"Okay," said the rancher. "You’d better park right here. Want to show you something."

Bob did as he was told. They got out of the truck in the cool, mountain air and began walking. Then the rancher put his hand on Bob’s shoulder and said, "Look up ahead."

My father-in-law walked slowly forward and then stopped dead in his tracks. Cleaving at right angles across their path—and across the pasture as far as he could see in both directions—was a yawning, black tear in the surface of the earth. Where they stood, the crack was probably 30 feet across. Peering over the edge, the hair on Bob’s neck bristled.

Where was the bottom?

The sheer, rock-ribbed sides of the great volcanic fissure plunged to unknown depths. Cold, still air seemed to exhale from the blackness below....

Walking back to the truck, Bob marveled at how difficult it was to see the fissure from just yards away....

Bob smiled to himself. Having a guide wasn’t such a bad thing! He gained a new appreciation for a man who knew the terrain—and where to park the truck.