The northern lights from a glass igloo

You arrive in Finnish Lapland in the blue hour, when the snow holds more light than the sky. The glass igloo is smaller than the photographs suggest and warmer than the outside air by some forty degrees. A domed roof of heated glass rises directly above the bed; beyond it stands a ring of frosted spruce and a horizon that will, if the night cooperates, turn green. The aurora is not a performance that begins on cue. It sits on an oval draped over the magnetic pole, and Lapland lies conveniently beneath it. Some nights it shows only as a pale grey arc that the camera reveals to be green; other nights it moves — curtains and pillars that shift faster than you expect and fade before you have decided what you saw. Staff wake guests when the readings climb, and there is an app that pretends to predict it, though a clear sky matters more than any forecast. What the glass igloo removes is the usual price of admission. There is no standing in a field losing feeling in your feet, no driving out to escape the light of a town. You lie under a quilt and watch the sky through the roof, and when the display fades you sleep rather than shiver. It is aurora-watching arranged for comfort, and that is precisely the point. Be honest with yourself before you book: the lights are weather and physics, not a booked event. Three or four nights gives the odds a fair chance; a single night is a gamble. Cloud can close the sky for a week, and no operator can promise otherwise. Dress for a few minutes outside, too — you will want to step onto the snow at least once, glass between you and the sky being no substitute for standing beneath it. What is guaranteed is the silence of a Lapland winter, the cold at the door, and a bed beneath open sky, which on the night it all arrives is as good as travel offers.