In the central desert of Iran lies a city called Yasd, known as the city of wind towers. The construction is from around the 1400 and is a form of natural convection used to cool homes and wells. The wind is caught at the top and funneled down, the effect is Astounding! I was surprised at how much cooler it was under the tower, literally several degrees Celsius!... I have been told that a well with this construction can keep a steady 10 degree C even if the temperature above rises to a scorching 40!