Learning From Ancient Fertilizer Factories

Talk about appropriate technology. They cooperate with nature on all levels — the design, the materials, the function... and gorgeous to look at besides. How would we build something like this today? This is very sexy stuff, even if it's all about pigeon poop. Click the image for a high-res narrated slideshow (or here for low-res.) From Jadid Online:

The pigeon towers of Isfahan are a perfect example of man working with nature in common alliance. Before the use of chemical fertilisers alternative means had to be found for generating large quantities of fertiliser. Using their knowledge of the natural environment the architects of Isfahan created pigeon towers. By attracting wild pigeons with seed and a safe place to roost the towers acted as a natural collection point for waste which could then be used as fertiliser. The Iranian filmmaker, Mohammad Saeed Mohasesi who has studied the pigeon towers of Isfahan explains the background to these ancient buildings.