I recently came across a report from 2011 about a house in Nigeria built with discarded plastic bottles and its viability as an option for sustainable construction.
While many may not wish to dwell in such a structure for innumerable socio-cultural reasons, one cannot deny the innovation in this idea. Not native to Nigeria, the methodology is known as bottle brick technology and is a very cheap and easy method for building eco friendly homes. The use plastic bottles helps to lower the cost of the building and reduce waste that traditionally ends up in landfills and gutters, thus helping to keep a clean environment. A double entendre of sorts.
The bottles are basically picked up off the streets and collected from rubbish dumps, then packed solid with soil and laid on top of each other, and finally bound with mud and string. The developers claim the buildings can withstand earthquakes and bullets, (A seemingly exaggerated claim if you ask me), and cost about a third of what it would cost to build a traditional block and mortar structure.