Glacier

The Glacier biome is a cold, snowy biome with varying heights. It has many packed ice and snow blocks. The Glacier biome is the coldest biome in the game, doubling the temperatures of Snowy Tundras and the like. As such, it is one of the hardest biomes to survive in.

Survivability
There are no trees, and very few mobs in the Glacier biome. One of the only mobs, the Ice Dragon, is an extremely dangerous one, making this biome even harder to survive in. Combine this with the extreme temperatures are this biome is very tough to prosper in.