Fruit walls, Paris, FranceFruit walls, Paris, France
Fruit walls, Paris, France

Thermal “fruit walls” grew increasingly popular in the 1600s, enabling urban farmers to grow “Mediterranean fruits and vegetables as far north as England and the Netherlands, using only renewable energy,” reports Kris De Decker of Low Tech Magazine. Absorbing solar heat by day, these masonry walls were able to raise temperatures by as much as 10 degrees Celsius (18 degrees Fahrenheit) at night.

Casey Tang