Surreptitiously crossing the Uzh river at 2am, with the full moon starting to set low on the horizon, the first thing that strikes you about the Chernobyl Exclusion Zone is the sound of it. Just two hours outside of Kiev, all the sounds of civilization disappear, and only our radiation dosimeters are left ticking softly with the wind.

But moving into the zone on the other side of the river, it's not silence we're met with. Even in the darkness, it's immediately clear that the forest has retaken the Chernobyl Zone, and the forest is alive. It's a reverberating symphony of birds, frogs, crickets, cicadas — even wolves howling in the distance. Navigating hesitantly through those first few kilometers, we moved as silently and nimbly as we could, in quiet awe to the sounds of life and the expanse of the moonlit trees around us.

And then, with the shock of a sound that doesn't belong, "WHAM-" a 6-liter bottle of water fell off the back of Geoff's bicycle, exploding when it hit the ground.

The three of us had decided to try to explore the zone by bicycle. Even after 30 years and an intensive 10-year remediation effort, it's a contaminated landscape. It's dangerous to consume anything from within the zone, since it could contain Strontium-90, which your body can mistake for calcium and absorb into your bones, eventually causing bone cancer. That meant we would have to carry in all the food and water we'd need for the duration of our trip. Hiking with food isn't so bad, but water?

We considered a number of options. Could we just carry it? No, we'd need at least 5 gallons each, which would mean 180lbs for the three of us. There was no way we'd make it 80 kilometers with that. Maybe a hand truck, or a wagon? Eventually we settled on bicycles, figuring that even if the terrain didn't always allow us to ride, we'd at least be able to push them with the water strapped to them.

10 minutes in, we were down 6 liters. We spent some time re-securing everything, all of us keen to avoid a situation where we'd have to make a choice between dehydration and drinking radioactive water.

Our immediate destination was the city of Pripyat. When the V.I. Lenin Nuclear Power Station was built, the closest major town was Chernobyl (14km away), which is how people came to refer to the plant. But a new city of 50,000 called Pripyat was built simultaneously with the plant to both house workers and serve as a utopian model for future Soviet development. This ghost city was our first destination.

We didn't know exactly what to expect for the trip, or if it would work at all. We had Google Maps satellite imagery, a rough idea of where the military checkpoints were, and a $5 compass. In the end, the easiest thing to do was just follow the old power lines.

It was 40km from the edge of the zone to Pripyat, and we wanted to be there before 7am, which is when we surmised that security would become more of an issue. We spent the night tiptoing around razor wire, coasting silently through sleeping checkpoints, and riding frantically through the dark from some surprisingly alert and vigilant guard dogs.

But mostly, we just gasped at the beauty and wonder of our surroundings. Watching an enormous buck with towering antlers cross through the twilight in front of us, it felt more like we were in some remote part of Alaska, but superimposed onto the rusting hammers and sickles of forgotten Soviet infrastructure.

It was a much longer and much harder ride than we expected. The sun came up at 4am, and we rode on through the early hours, pushing to reach Pripyat on time. Once or twice we considered ducking off in little abandoned villages we'd come across in order to wait out the day, but the radiation levels were always too high in the structures we found. So we kept riding, passing old rail yards, forgotten communist monuments, and rusting machinery. When we eventually found ourselves in the city, the lack of transition was surreal. As we were riding through the forest, willing ourselves to keep a steady pace after an all-night journey, we suddenly became aware that there were already 7-story apartment buildings looming up all around us, just behind the first few rows of trees. Block after block after block of giant imponderable buildings, all standing silently within the surrounding woods.

Exhausted, we picked an apartment building at random and went in. Our initial thought was to camp on the roof, but the radiation on the roof's surface was over 50 μSv/hr, so we moved to apartment #23 instead. The radiation there was only 0.08 μSv/hr (actually lower than our apartment in California). The former occupants must have had their windows closed when the explosion occurred. We collapsed and slept for most of the day.

When reactor No 4 exploded, there was a lot of initial confusion about the magnitude of the accident. For a number of reasons, it was a full 36 hours before authorities realized that four days in Pripyat would result in a lethal dose for its occupants, and finally ordered the evacuation. Residents were given 2 hours to pack whatever they could carry and get on a bus. Most were under the impression that they would be returning within 3 or 4 days, but they were never allowed back.

Looking at the newspapers and books scattered about apartment #23, the packed suitcases sitting where they were left, the clothes pins still sitting on the same clothes lines where they must have been 33 years ago, you can feel the abruptness of the city's end. This wasn't a ghost town that slowly petered out over decades until there was nobody left, it was a densely constructed city of 50 thousand where everyone left at the exact same moment, and nobody ever came back.

Our time in Pripyat was vivid. We'd have to hide and move cautiously during the day, but at night! The night was ours. We wandered around the rooftops, through the squares of the city, and into as many buildings as we could — each one more stunning than the one before.

We found the stadium, which underscores the vibe of the entire place: where the crumbling empty stands should look out onto the pitch, there is only forest. Standing in the bleachers, listening to the Pripyat municipal overture of resounding bird song, the only thing we could do was stare out at the trees and wonder "how long until New York looks like this?"

Over six hundred thousand people were directly involved in dealing with the aftermath of the Chernobyl explosion. The early days were filled with incredible sacrifice. Immediately after the accident, one of the first priorities was to put out the burning nuclear material that was sending a radioactive steam cloud billowing into the sky. Without a way to approach the reactor directly, they flew helicopter sorties over it with crews inside who threw bags of sand out the doors and into the crater, slowly filling it. When the sand started to melt, they did the same thing with lead. Some pilots flew up to 33 sorties into the steam cloud, and six hundred helicopter pilots were killed by the radiation.

When that material then started to smolder downwards out through the floor of the chamber, it threatened to come into contact with a large amount of water that had pooled there as a result of early firefighter attempts to put it out with hoses. This would have ignited a second reaction that would have been the equivalent of a 5 megaton explosion. It would have leveled Kiev and Minsk, and would have ejected the nuclear material from the other 3 Chernobyl reactors with a force that would have rendered much of Europe uninhabitable for hundreds of years. With only days to stop it, Alexei Ananenko, Valeri Bezpalov, and Boris Baranov went into the ruins of the plant, knowingly facing almost certain death from that level of radiation exposure, to release valves that would drain 5 million gallons of water.

When the same radioactive magma threatened to melt through the concrete pad below that and into the groundwater for 50 million people, miners dug a 150 meter tunnel 12ft under ground by hand to stop it.

When the firefighters from the first night, before they understood that this was not just a fire, showed up at the hospital sick and suffering from radiation burns, the medical staff there knew that they must have been severely contaminated, but they stayed and treated them anyway, potentially exposing themselves to the same fate.

Every interview I've seen or account that I've read from those involved, most of whom died within weeks or have suffered life-long health problems, has a common theme of no regrets; the sentiment almost universally "It had to be done. Who would I expect to do it instead of me?"

There's so much in Pripyat that by the time we had to leave, we had probably explored less than 1% of the city. We went out on the same road that the residents did 33 years ago. Riding across the zone under the full moon, we'd stop sometimes and stare out at the woods and fields around us, all alone in the middle of that huge seeming expanse. The experience is full of tensions. It is so beautiful and so peaceful that it really feels like paradise, but it's a paradise that you can't enjoy. You have to be careful about where you sit, what you eat, how you eat it, what you touch; which is — ironically — why it exists. The reason it's so beautiful and so peaceful is precisely because we can't consume it. Like, perhaps, all real paradises everywhere.

When we finally left the zone and made it back to Kiev, I was largely struck by how normal everything is there — there's almost no sign that the apocalypse is only 2hrs away. No physical signs at all, in fact. Around town there are statues of former princes, religious monuments, a memorial to the veterans of the Afghanistan war. On the bills of the currency, the faces of 10th century princes, politicians, poets, and writers.

What of the helicopter pilots who killed themselves to put out the most toxic fire in history? What about the people who knowingly sacrificed themselves to stop a reaction that would have destroyed most of Europe? Who were the miners that dug the tunnel through radioactive ground to save the water supply for 50 million people? They have no public monuments, we do not know their faces, their names are not etched onto the buildings that are still standing because of them.

I don't know all of their names, but I'm thinking of them here, in this place, amongst the living.