A frozen town is rising from the ice of the Ob Sea.
This is the Igloo Festival and construction is in full swing.
Participants are building the snow huts, dwellings traditionally used by Northern peoples.
Each snow block is placed on top of another at a slight angle, bending inward and spiralling upwards.
On top of the structure, the so-called keystone is placed.
If it is built correctly, it retains heat. The most important thing is that there are no gaps in the walls.
Not everyone achieves the ideal geometry.
It is especially difficult for beginners.
Each team is given two and a half hours to complete the construction.
The most important factor for victory is achieving the maximum floor area of the Igloo.
On average, experienced builders make an igloo of two meters in diameter and one and a half to two meters in height.
This year the weather was -16 degrees Celsius (3.2 Fahrenheit).
According to participants, this is rather mild compared to the last event when the temperatures dropped to -32 Celsius (-25.6 Fahrenheit).
One hundred and sixty-six teams are officially registered.
The oldest participant is 72 years old, the youngest just two.
Many come with their whole families.
A total of 123 igloos were built at the festival.
The bravest of builders stayed in their igloos overnight.