A wind Tower or the Barjeel is a traditional Persian architectural device used for many centuries to create natural ventilation in buildings. It is not known who first invented the windcatcher, but it still can be seen in many countries of the Arab world today.
Though constructing a wind tower is a thing of the past with the invention of the modern air conditioning systems, a handful still exist in most of the region’s cities, sometimes on people’s homes, and sometimes carefully preserved or reconstructed at museums.
Traditional wind towers rise five or six meters above a house. They are usually built of wood or stone but can also be made from canvas. The tower is open on all four sides and catches even small breezes. The breeze create a low pressure zone which will draw air up from the house causing to create natural ventilation.
The towers work amazingly well. Sitting beneath a wind tower even on a hot day you will feel a consistent breeze even when the outside air feels heavy and still.
I have taken the picture of the wind tower and the information from http://tabreedholding.com/About_UAE/Wind_Tower_Main.htm and wikipedia. I have colored it and given the light effects on photoshop.