Yakutsk, La Paz, Hammerfest and Bangkok are some of the harshest habitations in the world. Yakutsk: the coldest city on the planet. In this place known as “the cold pole”, the biggest challenge relates to the nature of the soil: the “permafrost”. With the warming of the climate, this frozen soil is melting and the buildings are threatened with collapse. La Paz: the highest capital in the world. Surrounded by 5 000 meter peaks, the city has always fought against nature to develop. Living at such an altitude is a permanent challenge to the human body. Hammerfest: a city in the dark. In the northernmost city in the world, the sun disappears for 2 months every winter. This perpetual night causes extreme effects on people, known as “polar stress syndrome”. Bangkok: the drowning city. With deadly typhoons, increasing rainfall, the rising of the sea level and a land subsiding at 4 cm per year, water has become the biggest threat to the city’s survival. Discover how these cities struggle against the toughest environmental conditions on our planet to provide their populations with an acceptable level of existence.