Temperatures drop to -5C within Sweden's famous ice hotel, located high above the Arctic Circle.
Built every October from the frozen waters of the nearby river Torne, the hotel has 35 bedrooms entirely carved from ice.
The hotel welcomes 50,000 day visitors every year for glimpses of hallways, bedrooms, and a wedding chapel sculpted from ice.
Rooms start at around three times the average price of a night in a three-star establishment in Stockholm.
Individual suites cost more, and feature sculptures and designs by artists from around the world.
Around 20,000 guests spend a night in the hotel every year.
One room inspired by the aurora borealis - the northern lights that can be seen in the skies nearby - features lighting that changes colour, as well as a giant snow sculpture of a reindeer's head, all set to a soundtrack of ambient music and, occasionally, reindeer grunts.
Guide Julia Hansers said guests usually react less to the cold than to the tranquility.
"A lot of people coming here live in the city, and there you always have some sort of sounds and noise around you, and inside the ice hotel it's completely quiet," said Hansers, peering out from under a thick woolly hat.
Bo Bjerggaard, a gallerist from Copenhagen, spent a night wrapped in a sleeping bag and a reindeer-skin throw.
"During the night I had to get up and then it was of course cold," Bjerggaard said, standing outside in the hotel's dazzling white courtyard made from snow.
"Then (it's) great again when you come back into the sleeping bag - you sleep so well because of the temperature," he said with a smile.
Guests can also enjoy a drink in the ice bar, where all beverages are served in glasses made from ice.
The hotel was founded in 1989 by a hotelier looking to attract visitors to the remote town of Jukkasjarvi, 200 kilometres north of the Arctic Circle.
Since 2016 the hotel has also used solar panels to generate electricity to cool a nearby building to below zero to allow them to keep 20 rooms frozen all year round.
When spring arrives, the winter hotel's rooms are closed and it melts back into the river until October, when construction begins again.