Ilulissat Icefjord is a 55-kilometre channel on the west coast of Greenland, packed so tightly with icebergs that you cannot see the water under them. The ice comes from Sermeq Kujalleq, the fastest-moving glacier on Earth, and a large share of Greenland's icebergs begin at its face. None of it gets out quickly. A shallow ridge of rock and gravel lies across the mouth, and the glacier's front reaches so far below sea level that the ice it drops hangs hundreds of metres underwater. Anything that deep grounds on the ridge, so the biggest bergs sit for months, breaking one another apart until they are light enough to float over it. A boardwalk leaves the edge of town and carries you across tundra to the cliffs at Sermermiut, high over the jam. You do not sit there long without hearing it: a berg splits with a crack you hear before you see anything move, rolls over, and pushes a swell across the water.
The cliff itself was lived on for four thousand years. Sermermiut was one of Greenland's largest settlements, occupied almost continuously from about 2400 BCE until the last families moved into town in 1850. A boat gives the ice its real size. Out in Disko Bay the floes that looked like white teeth from the cliff stand over your deck, and the boats keep well off: a berg that has melted far enough will roll without warning. Kittiwakes work the blue walls where cold, food-rich water wells up at the fjord mouth, and humpbacks feed among the ice from April to the end of September. From 21 May to 24 July the sun never sets, circling low through the small hours and turning the whole field pink, gold and blue at what ought to be midnight. For about six weeks around midwinter it never clears the horizon, and the aurora is up over the bergs by afternoon. Nothing leaves this fjord until it has broken itself small enough. The ice below the cliff looks the same at dusk as it did at noon, and it never goes quiet.