Kirk Etherton greets me by dropping a 25 pound boulder at my feet. He dove to the bottom of Walden Pond to excavate it. He tells me looking at the massive stone makes him think, “Did I really bring this up? It’s not like I was rescuing a stone baby. I mean, this took a long time. This took three attempts to bring to the surface.”

Etherton is a poet. But on hot summer days, the Somervillian takes up another art form: diving for rocks in Walden Pond. He excavates them, cleans them, and ties white cord around them. The cord is the length of how deep he dove for the rock. Technically, you're not supposed to remove rocks from state parks, but Etherton's never heard any complaints.

A rock Kirk Etheron retrieved from the depths of Walden Pond.
Courtesy of Kirk Etherton

As he dives at Walden, Etherton launches his body away from the shore and swims out to the middle of the pond to free dive. A white plastic canister with 20 feet of string tied around it floats behind him, rippling over his wake. He’ll unravel the string from the canister as he swims to the bottom. The deepest he’s ever gone is 28 feet.

“I’ll just take a deep breath. Dive down. Maybe I’ll see some fish," he explained before the plunge. "I’ll find a rock and then, when I’m tired, I’ll just swim around and do some other stuff.”

Each rock is selected with care. Through goggles he looks for layered sediment and speckled fractures on a stone’s surface, a natural sculpture. He looks for the most interesting rock he can find. But sometimes, even with goggles, it can be hard to see.

“Something might appear to be a good-sized rock, but  then, because of the distortion of the water ... you might have to move on and get something else," he said.

There's the sound of a sinking splash. A few minutes pass. Suddenly, Etherton pops up to the surface, gasping for air. He is pleased with his choice.

In the waters of Walden, Etherton feels truly comfortable. “I feel as though I am, essentially, largely a water creature. I feel more comfortable in the water than on land,” he said. 

He says that the bottom of Walden is like the surface of the moon. Just a 30 minute drive away from home to escape the world. He’s even written a poem about it, called "Dark Side of the Pond."

Kirk Etherton holds one of his treasures.
Tristan Cimini/WGBH News

Like any exploration, free diving comes with risks. “People who do this in a competitive way sometimes perish,” Etherton explained. He isn’t the only deep diver in Walden — some other divers have suggested he use tricks to dive deeper like flippers or even hyperventilation. He opts to do things, as Thoreau would have it, more simply. He reaches the bottom with just swim trunks and his lungs.

Etherton’s rocks are elegant and unembellished. “I like to do things that involve real things. You can’t get much more simple than taking an interesting rock and wrapping it with a string equal to the length at which you found it," he said. "One thing lead to another. I guess that’s how creation or creativity works for me.”

Etherton can't help but think about Thoreau while he dives for his rocks. “I always wonder what Thoreau would think of this ... Would he think it to be in the realm of living more simply? Or would he just think it was bizarre? I guess we’ll never know.”

"Dark Side of the Pond" 

Prepare for a launch from the surface, rippling and reflecting.

The countdown, inaudible, comes from the diaphragm: three ... two ... one: one last deep breath to last the length of this journey

beginning now with toes pointing, disappearing from the view of a horizontal lap-swimmer, appearing soon to the unblinking eyes of brown trout

ten feet down, passed by on this simple trip progressing into cool blue, blue-green, dark grey, darkness.

The scene through goggles 15 feet below and still descending is a journey through deep space: reference points gone, velocity uncertain, countless luminous particles suspended passing as a film of distant stars bending time.

Keep the trajectory with kicks and palm-thrusts — this soaring, climbing down now a feeling of leaving the earth, inverted ascent a working against buoyancy, not gravity.

At 18 feet below, the destination — the stark, silent bottom of Walden Pond — looms into dim-lit view; at

20 feet, the ice-water line of the thermocline offers its full-body embrace. The mission: find one fine rock to bring up from this lunar-like landscape, pulling it

from the slow-motion swirling silt, where it's been half-buried, glacier-dropped, waiting in time since before time was given a name.

(Hours or years later this rock will become a sculpture, a precious stone, a talisman.)

Now stand to survey this peaceful land. Now push off from 22 feet down to make the return trip, swimming toward widening light above with one free, non-stone-cradling hand.

Now splash-up into the world of trains, trees, voices and air.

Breath held must be released, but the rock retrieved can be held always, itself now held with a length of twine (equal to the depth where it was found)

wrapped around it securely—reminder of another, other-worldly realm: that aquatic, imperturbable, almost-dark-side-of-the-moon.