Structures 15 meters high and 25 meters wide - made out of snow.
For 70 years now, every winter, Sapporo, Japan, has hosted one of the largest snow festivals in the world: Sapporo Snow Festival. Each team has three weeks to create works of art the size of an apartment building from a few hundred tons of loose snow. Even a small mistake or a rise in temperature of 1°C - 2° C can cause an entire structure to collapse.