Grit speckled the ice pack as though blasted out of the earth and suspended in midair, boulders shattered and hung immobile in the dark of this catastrophic freeze. Nothing breathed here. This must once have been the deadest place on earth.

This surface interruption: a pale disk of light germinating in the snow-flecked sky suggests a radical tilt to the axis below, gales cede to gusts and vicious whirlwinds, ice giants shout in the night. An inch of silt marks a thousand years, an aeon means a single degree of arc, and by this scale a thaw is under way. There will be a century of centuries of snarling ice, an age of glacial strain until the first crystal’s glistening melt to liquid spreads and seeps and creeps north across the frozen surface to make of it a mirror wherein the sun might see its face. Light slaps and dazzles the ice, sends thick fronts of heated air against the polar cold. Meltwaters dribble between ice and rock, refreeze and melt again. The nights are cold enough to strip the lungs of any beast foolish enough to venture on this wasted acreage, the wind that blasts across the vista turns hide and flesh to stone. An ice-blink sky glares down at the nights’ reverses, which are boulder waste, scree and brine cells locked in rime. There are shelves where the sun never reaches, and salts forced by the pressure lie as powder on the surface.

But the days grow longer, water-sheets spread, mean temperatures rise and vent mists that boil off the blazing ice. Secret cables of water are trickling down and prising the frigid bole from its case of rock, meeting and joining on the stony floors that the sun cannot find. A thousand miles of ice floats in an inch of water.

Different orders are coming down the line. Crevasses and canyons rive the surface and snake forward, cutting loose immense crystals that shatter and collapse. Water runs at the bottom of ravines a thousand meters deep, eating out the lowest levels of the ice pack and rising until the whole is cut with rivers fed by their own corrosive increase. The landscape resounds with the crash of ice-columns and ice-arches, the unheard thunder of a million wrecks. Glassy ridges sink and settle in pools that lengthen and rise, become fissures, until this territory of waste is neither solid nor liquid, but an archipelago of drifting icebergs dwindling in a sea of their own dissolved bodies and a fog so thick with damp, it is neither air nor water. Unhinged mountains collide in the green subsurface light and send up rafts to the surface, where the sun can melt them. Small floes bob and rock in the water’s cradle while sunbeams draw them into the sky as clouds, which spread in filaments, snap, and shrink to nothing. Where there was ice, is water.

Still, this is an empty expanse. More temperate, more fluid, but the gulfs sprawl north and east, the central body curls south, then west, much as they did before. The change is local, confined to the westernmost strait, or most perceptible there. Are the northern mountains less towering, the Aland islands less numerous? Is the Landsort Deep sunk lower than before? The rise in water level is a matter of feet in a landscape of leagues, the product of differing coefficients–water expands, ice contracts–and yet this alone is not enough to drown islands and creep up cliffs. The movement runs deeper, reaches back farther. A compacted weight has lifted, an oppressed floor is rising, tilting back, and tipping water south and west toward the Belts and Sound of Zealand. Low rocky sills seem to shrink before the slow surge of the lakewaters, are overrun as the thaw reaches the northernmost coves. The breach is made and water races west to join the seething gray of an ocean that has waited some million years for the arrival of this, the last of its tributaries. Rocky lowlands offer little resistance to the forward flood; these shelving plains were always meant to be seabeds. Faster now, welling up and spilling over the scarps, forced on by the tilting basin at its back, the flood follows the lowest contours to meet the greater ocean. The battered coast is outflanked and overrun in one extraordinary moment as the first tongue of water trickles out of the dunes and runs down the shore, laps at the lapping waves, and tastes the ocean’s unfamiliar salt for the first time. An hour old and raw from the breach, it is the youngest sea on earth.

The thousand-mile ridge of rock that bars the northern gulfs from the ocean collects snow all through the dark of winter. Spring brings meltwaters tumbling down the mountainsides to boil in the ravines. A water table of distant plateaus and barren fells feeds great rivers to the north and east. Showers are frequent, though rarely sustained for long. Short hot summers give way to drizzly autumns. The first men to gaze on these waters would have found a placid, temperate sea, thick with reed-beds. About its southernmost coast–for they came from the south–the waters meandered haphazardly, prising intricate spits and bodden out of the coast, baring reddish sandstone to the blast of the odd winter gale. Healing drifts of clay covered the ice-scarred granite of the seabed, purple heather shaded the long humps of eskers and drumlins back into a boggy foreshore. They were easy waters, and the thick forests of oak and beech through which they must have traveled might have supplied the timbers for a vessel. But something deterred them and sent them east along the shore rather than north across the sea. Some journeys are irresistible, some no more than the thudding of feet. They set their sunburned faces toward the interior mysteries and left behind them vague currents, placid convections and stirrings. Drift.

This strange and gentle sea, reed-fringed and resting in a granite cradle still rocking in the aftermath of ice, dotted with islands and bounded with stony northern coasts, fed by melted snow and rainwater, almost enclosed behind the jut of the peninsula, yet appears somehow lacustrine, an outbreak of water arrested at the edge of the ocean, frozen in the moment of joining. The bulk and heave of brine calls from beyond the strait, but its newest dominion still clings to an earlier being, of a freezing and preservative stillness. Weak inflows through Skagerrak and Kattegat signal distant oceanic storms, but mostly the sluggish currents roll under the impetus of debouching rainfall and snow. These yeasty yellow waters are almost saltless, almost tideless, almost stagnant in the deeps of Arkona or Landsort. The northern gulfs still freeze over five winters in ten. This sea will always keep something of the character of ice.

The first men never returned. Peat-bogs, beech scrub, and moorland lay undisturbed for centuries while fish entered by the Belts, spawned in the brackish waters, grew fat on sea snails, brown shrimps, bristle worms, and soft-shelled crabs. Atlantic salmon sped east with the sea trout and grayling to spawn in the great rivers whose mouths in summer would choke with the bodies of spent lampreys until shrieking gulls and goosanders plucked them from the water. Flounder, dab, sand eels, and lumpsuckers grazed the saline bottom waters while gudgeon, pike, and dace hovered about the freshwater outflows. Cod spawned in Arkona Deep, grew huge, ate each other. The spring and autumn herring founded their colonies in the nearby shallows off the islands of R”gen and Use-dom. A million undisturbed existences floated, swam, spawned, and died before the first keel cut the waves above and the nets descended to haul the sea’s fat harvest ashore. Invasions, battles, and slaughter were a vague clangor, dim thuds in the deathly air; the pale bodies sank quietly, watched by lidless, curious eyes. Spars and planks drifted off the exploded coast. Dim shapes sank amidst the skerries.

Herring-lives circled such interruptions; supple cycles of eating and breeding stretched to allow their passage. Storms had brought no more than the puny challenge of barrel staves and broken oars in the past. As the rising wind churned the surface they would sink, whole shoals diving for shelter in the lee of the cliff, until the swell died down and they could rise to feed. This storm was different, its course bending away from them, its first shudders familiar enough, but then exceeding all they had known before. They dived and waited, but the storm only roiled and thudded overhead, a bludgeoning throb reaching deeper than ever before. In the deep off Usedom, they shook as the tempest tore loose sea-grass and kelp, sent fogs of clay billowing out of the trenches, buried its violence in the depths. They never suspected the transaction taking place above, so stubbornly held by the spit running off the line of the coast, so violent a wresting as the waves clawed this gift for them from the land. The thrashing surface-creatures above were yielding up a surpassing tribute to the waiting shoals, greater and more intricate, different in kind as well as scale, and more enduring.

The herring knew the coastal cities as compacted secrets, the ends of tunnels emerging at night under a moonless sky. Looping wakes converged there, linking each to each, one confirming the next as the vessels passed overhead with their dim shouts and the pressure of the hulls fumbling dully in the depths like minor showers on their way to somewhere else. The herring tracked them home to port, suffered gray death in the nets that were hauled aboard with the full-grown fish strung about the middle, trying to jackknife free and drowning as the threads tightened over their gills. A foaming cloak of scum protected these places from prying herring eyes, thickening about the piers, breaking up in the wash beyond the headlands. Such a traffic, such a thickening of these solitary creatures. Hungry places, these cities. But beyond the vague maw, the strange tightening and deadening of currents, where were the teeth, the gullet, the stomach?

This: felt first as a distant disturbance in the storm’s fury, a vast crumbling or drawn-out collapse. Out of the battered cliff, great shards of clay were coming loose. Slabs of sandstone tumbled free, crashing down the sheer edge and dropping into the deep. The sea took great swings at the spit, cutting away until the weight above drove down its own foundation and followed it into the waters. A massive submergence, a vast pulse of pressure, clay misting and clogging their eyes and gills, clearing and revealing to them the scale of the displacement. Greater than the greatest vessel, this awaited mystery still locked in the aftermath of its deliverance, too strange and exceeding them all as it lowered itself to the seabed. There it was, laid out below the shoal, with all its people, buildings, carts, and livestock stretching farther than they could see with the reek they had tasted before only from a distance. Here it was thick and strong, all the tantalizing stenches blended together and curling thickly through the water. They waited and felt the surface grow calm. They saw each other’s fat silver bodies turn this way and that before the yielded gift. And then the first few flipped their tails and descended. The thrashing creatures above had delivered as tribute a city.

The older herring swam with its citizens, circled their temples, and overlooked their marts. Paddling in and out the doors and windows, they sought out the clumsy giants in flowing robes who promenaded through the drowned streets. Lurching in the waters’ flow, they were more like plants than men. The herring rose, and sank, and rose again. Other shoals gathered about them. The upper waters glittered with fry. They would never forget the pact forged in the storm. The city would grow familiar to them as the sea-floor itself, and in time indistinguishable.

Gifts and years: bladderwrack creeps closer to the shore, loamy soils flocculate and wash away. Near tidelessness means the survival of low landscapes and improbable islands. Sharks’ teeth and whalejaws are the oldest bones in the sea. Weed rafts drift and are blown by northerly gusts into estuaries and lagoons. Sinking canvas wheels down into the darkness, goblets and bracelets glitter and are eclipsed. Spear shafts, scabbards, rope-ends, and corn sacks take their own trajectories through the fathoms. Smashed hulls lurch while mastheads dive, but all are voided and deposited on the seabed. Surface-creatures drown. If the ice was a barrier no object could breach, then the sea that took its place will accept all; a subtler poison, for everything sinks in the end. The herring understand. Not since the city–and that was a hundred generations before–have they clustered so thickly and so curiously as now. The tribute from above is always puzzling and clumsy, always awkward and misshapen; this is no exception. And yet it neither floats nor sinks, seeming to hover in the water like themselves. They move closer, and it begins to shake. They feel the waters agitate around it. A booming sound resonates with their otoliths, and their fins begin to twitch. It is almost invisible in the murk of these depths; something hangs beneath it. What? Is this finally the key to the mystery of the city? Something snakes away above, tautens as they circle slowly, comes loose, and disappears. The larger fish butt against the intruder. These are herring waters and this is the coldest water-layer. But perhaps they were mistaken, for it seems to be sinking now, tumbling down out of sight. Some turn away as deepwater currents take the intruder, weird tribute from above, drifting in the saltless tideless waters fed by meltwater springs, racked by memories of ice, scourged by serrated coasts, darker and deeper and farther down toward the city. Lost? No, not quite. Blunt herring noses butt against its sides. Their curiosity sustains it; its own weirdness buoys it up. But what? In this sea a barrel is sinking, and in this barrel is a man.