The drawings were stick figures of men, rectangular grids, and most notably, a tall sailing ship, complete with a mast and furled sail.

"There’s some petroglyphs over in Pinto Canyon," Frank said as he passed me on the trail. Frank Johnson, a handsome 75-year-old man, with flowing white hair and a superb knowledge of hiking trails, is something of a Sierra Club celebrity, and he was leading our hike into Fossil Canyon — just south of the Anza-Borrego Desert State Park. I was frustrated that a man of his age could outpace me, but I’d never hiked ten miles in the sand before. Frank’s words about petroglyphs startled me because during 20 years of hiking I had never seen one. Now here I was with a dozen tough old Sierra Club hikers who had seen so many as to not give a damn. I knew that they’d protect these historic sites by not giving out their exact locations, so when I finally caught up to Frank again, I was cautious about asking him where Pinto Canyon was.

“Get yourself a USGS map for In-Koh-Pah Gorge,” he said. “Then follow the international border east from Jacumba until you reach Pinto Canyon. The pictographs are located directly under the letter P, where the word Pinto is printed on the map.”

Grateful for the information, the next day I bought the map at Adventure 16 in Solana Beach. That evening, my friend Michael and I examined it. Pinto Canyon was right where Frank had said, about eight miles south of Interstate 8, between the Jacumba Mountains and the Yuma Desert. The small canyon meandered from inside the United States down toward the town of La Rumorosa, in Mexico.

I wanted to get a couple of sturdy friends and hike to the canyon immediately, but a closer look at the map revealed some very rugged terrain. Furthermore, there’d be no water or emergency assistance of any kind available during the hike. We’d have to carry everything we’d need. We’d need at least a gallon of water per person, per day, and more in case of emergency. That meant about 20 pounds of water sloshing around in our backpacks in addition to the camping gear.

Out in the desert, if you run out of water, you’re going to die. The notion that you can satisfy your thirst by cutting into a cactus is mostly fiction. Cacti are tough, covered with stiff needles, and filled with nothing more than warm pulp. So your time out hiking in the desert is strictly limited by the amount of water you can carry. A hiker who gets lost and runs out of water is going to perish. Besides being as dry as a bone, the area around Pinto Canyon has other dangers. Because of the canyon’s proximity to the international border there’s the risk of running banditos, “mules” carrying drugs, or “coyotes” leading groups of migrants into the United States. My hiking buddies and I were capable of traversing difficult terrain, but we weren’t accustomed to running into armed men, or desperate, perhaps even starving people.

But my desire to see these petroglyphs was stronger than my fear, so I prepared for the Pinto Canyon hike by making a dozen or more day hikes in the nearby Jacumba Mountains. As both my confidence and that of my hiking partners increased, we allowed ourselves to hike farther and farther out into the desert.

Patrick Brady accompanied me on one of the early hikes. We met on a Sunday morning at the Coffee Bean in Del Mar, where he and his brothers Raymond and Noel hang out. The Bradys are Irish. Patrick is an artist who runs an apple orchard up in Julian. Raymond and Noel work in construction. They’re tough — the kind of men a little guy like me needs to accompany him in rough country. I was a little worried because it was September and it was going to be hot. But the heat didn’t dissuade Patrick. He and his brothers worshipped the sun. They often drove out to Borrego just to escape the fog along the coast. So a hike out near Ocotillo Wells would be right up their alley.

Patrick and I climbed into the car and got started. We had a long drive. From Del Mar we took the I–5 south to the I–8 east. We drove through El Cajon, Alpine, Pine Valley, Descanso, and Jacumba. Then just past the San Diego county line, we exited the freeway at Mountain Springs Road. The Mountain Springs exit doesn’t go anywhere, but it gives drivers a place to turn around if they have to. The border patrol agents who watch this sector lay a wary eye on anybody who gets off the freeway here. This is a popular place at night, when coyotes load their trail-weary customers into cars for transportation north to Los Angeles and elsewhere.

Patrick and I drove under the freeway and onto a dirt road, which leads to the remnants of old Highway 80. Built in 1926, the foot-thick steel-reinforced road looks as though it was built yesterday. We parked at the end of the highway and put our backpacks on. There was a dangerous descent onto Interstate 8, then a mad dash across it, after which we entered a sandy wash — pristine except for the footprints of a dozen people headed northward. Patrick and I stopped to explore an old abandoned stone structure, which may have been the Mountain Springs stagecoach stop. Inside the old building, we found rusty mattress springs, empty tins, an old cast-iron stove, and lots of mouse droppings. There was absolutely no trash or graffiti inside the old building — a surprise, since we were only 200 yards from a major freeway. On the other hand, it is a testament to just how empty and desolate this country is.

We left the old house and climbed the high, boulder-covered hill behind it. This was my favorite kind of hiking — diverse terrain, places of historical interest, and the possibility of discovery. It was about 90 degrees and I was baking. I was a little worried since Patrick hadn’t drunk any of his water. He was more interested in smoking American Spirit cigarettes. Maybe the nicotine dulled his thirst. Anyway, up near the top of the hill, we saw three huge boulders pressed together. There was a sandy patch between them, with a thin shaft of sunlight streaming down into the center. I wanted to go inside to get out of the sun, but the opening to the room was small. So I got down on my stomach and crawled in like a snake. Inside, I was shocked at what I saw. Sitting near the edge of the room was a huge Indian pot, maybe 16 inches high and a foot in diameter. It had a lateral crack but was otherwise in good shape. I scanned the rest of the room but saw nothing else. Lying there in the sand, I felt as if I had just gone back 500 years. I almost expected a old Indian to pop out. Patrick crawled in after me and gasped. In hushed voices we talked about the irony of finding this old pot here — just a couple hundred yards above Interstate 8. On the busy freeway below, carloads of people raced toward El Centro. But here inside this small cave, we sat with the ghosts of the area’s first inhabitants, a Native American culture that struggled to survive in this rugged and unforgiving country. I finally bummed one of Patrick’s cigarettes and lit up. The two of us blew smoke rings out to the Great Spirit.

I returned to the area a month later with my friend Michael. I had piqued his interest with the news that Patrick and I had discovered the big pot. Michael had been taking a wilderness-survival course with the Sierra Club, so he was in perfect physical shape for an afternoon of exploration. During the drive out, we decided not to climb the same hill as Patrick and I had, but to hike around its base, which would be about six miles around. We started by entering a beautiful palm-filled canyon on the south side of I–8. Even though the canyon’s sandy floor was dry, we felt a sudden drop in temperature from the moisture in the air. This shady environment was a welcome contrast to the heat and blazing sunshine on the hillsides around us.

While Michael checked out some Indian grinding holes, or “morteros,” I inspected a single set of tracks leading ahead of us in the sand. The impressions reminded me of the combat boots I had worn in the military. That, plus the fact that the person wearing them was headed south, led me to conclude that either a hunter or a border patrol agent was ahead of us in the canyon. I knew that agents were skilled at following tracks left by other people. An experienced agent can ascertain many useful things, such as the walker’s gender and weight, their speed and direction, mental clarity, and whether or not they’re trying to avoid detection. I’ve also read that an agent can tell from the depth of a person’s tracks if they’re wearing a heavy backpack, as might someone who was carrying drugs.

We continued up the canyon, and within minutes we saw the man ahead of us. It was a lone U.S. Border Patrol agent in a green uniform, with a radio and a handgun on his belt. I knew that he wouldn’t like being followed, so I called out a greeting. He was startled, and I saw him move his hand over his holstered pistol. We walked on up and made small talk. The agent’s last name was Ramirez, and he was very polite. I thought it ironic that a Latino would be out here trying to keep other Latinos from illegally entering the United States. Anyway, I told Ramirez about the terrific pot we’d seen up on the hill, and how we hoped to hike to Pinto Canyon later in the season to see its petroglyphs. Ramirez shook his head and grimaced. He said that Pinto Canyon was a dangerous area, more of a war zone than a hiking destination. He said that for safety we should hike with a larger group and try to stay up north, inside Anza-Borrego Desert State Park. We thanked him but ignored his advice.

The canyon Michael and I were in eventually petered out onto a wide flat plain. After about a mile, I bent down to get some cactus needles out of my boot. I was surprised to see dozens of pottery fragments on the ground, most the size of a quarter or smaller. Further examination revealed that the whole area contained fragments. It looked like the area might have supported a large tribe — as opposed to just a place where a few individuals came for fresh water, as the stagecoach obviously had.

As we hiked on, we became more aware of footprints in the sand. Where before only a few had trod now there were groups of 20 or more. As always, the footprints led northward, toward the freeway. We also found hundreds of empty plastic water bottles from Mexican supermarkets. Michael and I really wanted to recycle all that ugly plastic, but we would’ve needed a dump truck to haul it. We walked another mile or so and came to something we should’ve expected. Sitting in the middle of nowhere was a big red Samsonite suitcase. It looked so out of place there in the desert that both of us just stood and stared. Finally, I gave in an opened it up. As I unzipped the cover, I thought about the movie White Sands. In it, a small town sheriff finds a half-million dollars in cash on top of a desolate butte. Unfortunately, our red Samsonite didn’t have any cash, only a new pair of Nikes, various articles of female clothing, an address book, and airline tickets — from Guadalajara to Mexicali — dated five days before.

The feeling you have while looking through someone else’s suitcase must be similar to what a detective feels while they investigate a crime scene. You’re trying to solve a puzzle using clues provided by the victim. The clues in this case showed that a Mexican woman had abandoned her suitcase while crossing into the United States. She was desperate, and judging by the red suitcase with its tiny wheels stuck in the sand, she was ill prepared. But we were grateful to have found only the suitcase and not its owner. The daylight was fading and neither of us wanted to be out here at night. So instead of finishing our hike around the hills, we cut directly over them and hiked straight to the car. In all we had spent five hours outdoors in 90 degree weather, and we were both very tired.

The agent’s description of Pinto Canyon being something of a war zone was confirmed in the news. Operation Gatekeeper has fortified the border areas at Tijuana, Mexicali, and El Paso so well that thousands of illegal immigrants are now choosing to cross the open desert — often with disastrous results.

While I was in Maui photographing a wedding, my friend Michael went on another Sierra Club hike. Their group made a quick one-day trip from Mountain Springs Road to the top of Pinto Canyon, a 12-mile hike. They didn’t hike far enough down the canyon to see the petroglyphs, but they stumbled upon something quite horrible. Michael told me that he was about 100 feet ahead of the group when he saw something in the sand. What at first appeared to be a pile of clothing turned out to be a dead girl of approximately 12. She was wearing a small backpack, and judging by the mummified look of her skin, it appeared that she’d been there for several weeks. The rest of the group caught up with Michael, and a couple of them got sick. Someone guessed that the girl might have died suddenly from heat stroke. Later in the afternoon, the leader of the group reported the body and its location to the Border Patrol.

Despite that terrible news, I returned to the area a few weeks later with my friend Tom. Tom is a professional photographer and a veteran of many rugged adventures. He’d hiked to Havasu Falls in the Grand Canyon and had just come back from a weeklong backpacking trip in Utah’s Escalante Canyon. Regardless of Tom’s experience, I knew that he was absent-minded and often forgot to bring essential things. Like the one time when he was three hours late meeting me for a hike. When he finally arrived at the Pacific Crest Trailhead, he had forgotten to bring his hiking boots and water.

But Tom had jumped at my invitation to accompany me to the petroglyphs, and I was glad to have him along. At the car we divided things up. We got two gallons of water each. I got the tent and he got the ground cloth. Tom insisted on bringing a professional four-by-five camera and tripod, so he could take some highly detailed pictures of the petroglyphs when we found them. To accommodate the big camera, he chose to leave his sleeping bag in the car. Tom was older, stronger, and more experienced than me, so I was not in a position to second-guess him about leaving his sleeping bag. But I didn’t understand why he couldn’t just bring a regular 35mm camera.

I felt well prepared. I’d spent the previous evening pouring over my USGS map, penciling in compass headings both in and out of Pinto Canyon. I’d noted some obvious geographic references, like pointy volcanic peaks and dry lakes, so we could judge our position visually. The only thing we didn’t have was a handgun, which would have increased my sense of security. Tom and I had talked about it, but we decided that stealth would be the best defense.

We crossed the freeway and headed directly up the ridge. I was mortified by the weight of my backpack. I carried 60 additional pounds with each step and balancing was difficult. It took us an hour just to reach the 100-foot-high ridge above the freeway. It was back breaking, but at least it wasn’t hot. In fact, it was cloudy and there was a chill in the air. The cold weather and the discovery of the child’s dead body had cast an ominous shadow over this outing. As I walked, I had the acute feeling that something bad was going to happen and that we had better get in and get out as quickly as possible. I felt as if we might walk around a bend and right into a dozen desperate immigrants, either lost or being led by an armed coyote. Neither of us had any idea how we’d react if this happened. But as we continued, the land opened up, and it was obvious that we were very much alone.

We stopped often to examine the country ahead of us. There was no trail to where we were going, and the geography changed constantly. We couldn’t follow the compass headings I’d charted because the terrain simply wouldn’t allow it. A high cliff or a mile of high boulders would impede us. Therefore, we used the visual references I’d established. We’d hike toward a tall cinder cone for an hour, then when we reached it, we’d hike toward another landmark farther on. Surprisingly, this vague system worked.

We reached the upper part of Pinto Canyon about five hours after we left the car. We wanted our campsite to be hidden, so we set the tent up in a low area surrounded by mesquite. Once the tent was up and the packs were stowed inside, we hiked on down into the canyon. I had waited over a year for this moment. The inherent danger only increased the rich sense of discovery I felt. The canyon was narrower than I expected, but it was very pretty. There was a rich contrast between the nearly vertical rock walls and the soft, almost sensual sandy floor. The canyon turned so frequently that you never knew what lay ahead. Occasionally, we found small pools of water, and there was evidence that at times much of it had flowed. Tom was carrying his large camera and tripod, and we scanned the canyon walls for the petroglyphs. About an hour later, we came upon them. There were three flat rocks covered with crude drawings, right at eye level. The marks had been made by scratching the top layer of rock off, revealing a lighter colored layer underneath. The drawings were stick figures of men, rectangular grids, and most notably, a tall sailing ship, complete with a mast and furled sail. It sounds stupid, but after waiting a lifetime to see a petroglyph I was unhappy to find a drawing of a sailing ship. Damn! Where were the woolly mammoths and saber-toothed tigers? A crudely drawn picture of a sailing ship meant that the drawings weren’t more than 400 years old. The artist may have spent time at the San Diego mission and had seen a Spanish supply ship sail into port. It was interesting but not the least bit ancient. Tom shot some photographs, then we headed back to camp.

After dark, we made a small fire, and I made tuna macaroni. I’d been making tuna macaroni since I was in the Boy Scouts. It’s easy to make, and it’s filling. Since Tom had left his sleeping bag behind, he tried to form a bed by using my down jacket and other loose articles of clothing. He took what would have been my pillow and put it under his back. It was bitter cold, and our cheap tent flapped in the wind constantly. As though there wasn’t enough noise, at about 2:00 in the morning a Border Patrol helicopter flew overhead. The agents onboard used a loudspeaker to tell a group of immigrants to stay where they were. Then they landed nearby and held the people until agents with vehicles could arrive. The result of all that activity, combined with Tom’s constant twisting and turning, was that neither of us got a wink of sleep.

In the morning, we were both irritable. I used a precious quart of my water to make us some hot oatmeal for breakfast. Tom accepted the bowl I gave to him, and then he added some of my brown sugar and soymilk. He ate a single spoonful then immediately spit it out. Then he emptied the rest of his bowl in the dirt. I was furious. Tom made a face and said it tasted horrible. I took a spoonful from the pan, and it was horrible. I’d accidentally brought rye flakes instead of oatmeal. Tom was grouchy and ate a granola bar. We were miserable — exhausted from the previous day’s hike and total lack of sleep. It looked like it was going to rain, so we decided to hightail it out of there. We ditched the lousy tent, sleeping bag, and ground cloth, leaving them for some lucky passerby. Then we threw on our lightened packs and started back.

For the first couple of miles, we followed our route from the previous day, but after that it was a crapshoot. We argued about the quickest way back to the car and wound up taking separate routes. This was reckless, since we had only each other for protection in this wild country, but sometimes a divorce is just what the relationship needs. I had chosen to follow an old jeep trail, even though it wasn’t headed toward our car. I figured it would be easier to walk on an established trail than to struggle through the same labyrinth of broken boulders that we’d struggled through the day before. It turned out that my trail was quicker, but after two hours the sun came out, and I found myself hot and delirious. I had to sit down often, take my compass out, and confirm my heading. The jeep trail I’d followed had brought me miles off course, and I was in unfamiliar territory. I had a sense of what it might feel like to be an immigrant, separated from his group. Confusion from low blood sugar, compounded by fear. But at least I didn’t have to try to evade the authorities.

I was hot and tired, so I sat down in the shade of an overhanging cliff. I ate an apple and drank a little from my last quart of water. I had become quite desperate. I was weak, and the fear I felt was paralyzing me. I was very aware that I could die out there if I didn’t find a direct route back to our car. So I opened my map and laid the compass on top of it. I aligned the map toward the north. On the map I found the old jeep trail I had hiked on, and I used it to approximate where I was. I drew a line on the map from that point to the place we’d parked our car, and I used the compass to give me a heading to it. Then I picked my stuff up and started walking in that direction. Instead of deviating around hills, I climbed over them, so I could stay on course. Another hour went by, but then, as I reached the top of a hill, I saw something strange off in the distance. It was a tractor trailer headed east on Interstate 8. I still remember the big Walmart logo printed on the side. I’d been saved. I reached the car an hour later and met up with Tom. We hugged each other and washed our faces with the last of our water.

Listen to Robert Marcos discuss his adventures further on Reader Radio.