I.
Last year, the media personality Lauren Sánchez — newly engaged at the time to Amazon billionaire Jeff Bezos — conducted a tour of her fiancé’s ranch for a profile in Vogue. Accompanied by the journalist Chloe Malle, Sánchez landed a helicopter in the Sierra Diablo, a small mountain range in Texas, and descended a spiral staircase carved directly into the rock. She had been photographed there already by Annie Leibovitz, lounging in a red Dolce & Gabbana dress below the gears of a monumental underground clock designed to run for ten thousand years. As Sánchez explained, “It represents thinking about the future.”

The clock isn’t open to outsiders yet, but an enterprising trespasser could conceivably check it out now, based solely on public information. It’s at 31°26’54”N, 104°54’14”W, about eight miles due west from the Blue Origin landing pad that Bezos once used for a suborbital flight on one of his own rockets. The easiest approach would be to fly into El Paso, rent a car, and head off before sunrise. After driving a couple of hours east on I-10, get on Highway 54 in the nondescript town of Van Horn and continue north for thirty minutes.

As you proceed into the desert, keep an eye out on your left for a white gate leading to a side road. Pull over when you see a notice reading “Private Property — No Trespassing,” next to a sign with the name and number of a local stone supplier. A small red “2” on the gate is the only indication of the owner’s identity. If you like, you could go up the highway to the nearby headquarters of the Figure 2 Ranch, which Bezos bought two decades ago, and ask to see the clock, although you might have better luck striking out on your own.

Once you manage to bypass the gate — which is illegal but not difficult — keep going west along Marvel Road. Instead of driving directly toward the line of mountains straight ahead, take the first right on a narrow dirt path, bearing north, and then turn left on a road little more than a scratch in the dust. Follow it to a trailhead in the limestone hills of Mine Canyon, where the route becomes impassable by car. You’ll cover the rest on foot. 

At first, your destination on the peak is visible through binoculars, but it soon disappears from view. The trail is fringed with cacti, thorns, and bear grass, and at one point, you need to slip through a tight slot between two rock walls. Most of your hike occurs on a series of switchbacks surfaced with crushed stone, aided when necessary by chain ladders. As the crow flies, it’s less than two miles from where you parked, but the winding path is over twice as long, gradually rising to almost two thousand feet above the valley floor.

A hard walk of three hours brings you to a sheer cliff facing south. The vertical crags seem unclimbable, but you eventually see a cavelike opening. Although it blends into its surroundings, it’s clearly artificial, leading to a perfectly round entrance framed in wood beams and ending in a weathered mesh gate, like the doorway of a mine. Inside, you turn a crank to switch on a light, revealing a ladder leading down to a natural cavern filled with stalagmites. As you move into the dark, you need to crouch, groping toward a small hole at the rear of the cave.

Squeezing through, you enter a manmade passage terminating in a smooth metal wall. At the center is an oval door, like an airlock, hinged to open upward with a handle at the bottom. Beyond it is an identical door, which opens only after the first one is shut. Heading toward a faint light around the corner of the next tunnel, you emerge near the base of a cylindrical shaft, five hundred feet high and twelve and a half feet in diameter. Along the inner wall, stone stairs spiral upward, the railing at the height of your waist. The temperature is a cool 55 degrees Fahrenheit. 

Ascending the steps, you climb toward a spot of light that shines down from somewhere far above. At seventy feet up — assuming that you’re lucky enough to visit after everything has been fully installed — you reach the lowermost part of the clock. Suspended from a rod is the driveweight of the power system, a gigantic concrete oval, edged in bronze, that weighs something like five tons. As you continue onward, you start to get a sense of the clock’s enormous size — the mechanism alone is over two hundred feet high.

Next is a platform equipped with a horizontal windlass, like a capstan on a ship, with three curved bars at chest level. By walking in a clockwise circle, visitors can wind a rack gear to slowly raise the counterweight over the course of eight hours. For now, you move past the steel and titanium gears to the eighty-foot Geneva drive — a very slow computer with twenty notched wheels — that controls the chimes. At noon, if the clock is wound, ten bells ring in one of 3,628,800 unique patterns, enough for a different sequence nearly every day for ten thousand years. 

Arriving at the primary chamber, you see the brass and quartz enclosure that protects the calculation system, the escapement, and a pendulum that completes one swing every seven seconds. The clock face itself is eight feet across. At the center is the black globe of a star field, encircled by movable rings that indicate sunrise, sunset, and the phases of the moon. The outermost ring gives the year, with room for five digits, and a readout for the current time is buried deeper inside. To update the display, which has been paused since the last visit, you rotate a small wheel by hand. 

Gazing upward, you discover that the source of light overhead is a cupola with sapphire windows. At noon on the summer solstice, sunlight is focused on a solar synchronizer, activating a trigger that corrects for the drift of the pendulum. Throughout the year, the sun also heats a chamber of air, with the temperature difference between day and night driving the piston that powers the timing system. Even without winding, the clock can run indefinitely. 

Before you reach the cupola, however, you find that the staircase is growing narrower. Eventually, the steps taper so much that it’s impossible to keep going. Since you can’t take that route to the top, you realize that the designers want you to rethink your plan. In the words of Danny Hillis, the man who conceived the clock in 1989, long before Bezos became involved: “You have to get away from the idea of direct progress and surrender that kind of control in order to find your way.”

According to Hillis — who originally planned to build the clock himself — some of his friends saw the project as a symptom of “a midlife crisis.” Born in 1956, he had written his thesis at MIT on parallel computing, an innovative architecture based on simultaneous calculations by thousands of ordinary microprocessors, and co-founded a supercomputer startup called Thinking Machines. Its most famous product was the Connection Machine, a black cube with blinking red lights that was so photogenic that Steven Spielberg featured it in Jurassic Park.

In 1994, the company went bankrupt. While the Connection Machine worked well for certain applications, like weather modeling, it was hard to program and had trouble attracting commercial clients. For the breakthroughs that Hillis had in mind, he conceded, parallel processing had to improve “by a factor of a thousand, maybe a million.” Hillis had been on the right track, but a decade too early, so perhaps it was unsurprising that he would quit the race to build faster computers,  hoping instead to regain his sense of  deep time. 

He had been dreaming about the clock for years, but he first set it down in detail in an essay — later published in Wired — dated February 15, 1995. Noting that society had trouble picturing the far future, he proposed a symbolic object to encourage long-term thinking: “I want to build a clock that ticks once a year. The century hand advances once every one hundred years, and the cuckoo comes out on the millennium.” It would keep accurate time for ten millennia, or roughly as long as human civilization had already existed. The